Chief Dominick J. Arena of the Edgartown police yesterday filed application for a complaint against Sen. Edward M. Kennedy for leaving the scene of an accident on Chappaquiddick, in which Miss Mary Jo Kopechne of Washington, D. C., was drowned. Senator Kennedy has admitted that he was the driver of the automobile that ran off the Dike Bridge and sank in Poucha Pond, with Miss Kopechne trapped inside.

As is his right under the statute, Senator Kennedy through an attorney, Richard J. McCarron of Edgartown, has requested a hearing on the issuance of the complaint, and the date for the hearing has been set for July 28. Normally, such hearings are held before the clerk of district court, Thomas A. Teller, but yesterday it had not been determined whether Mr. Teller would preside or would turn the hearing over to the presiding judge of the district court, Judge James A. Boyle.

The accident occurred about midnight on Friday, and since then the story has unfolded through a series of bizarre revelations and has grown, as far as the Vineyard is concerned, into something more than the story of a tragic incident. The principal figure still remains Senator Kennedy, but the most visible figures in the story are the men and women who have made up the not-so-small army of newsmen, reporters and TV camera men who almost magically began to appear as soon as word of the accident and the involvement of the senator got out.

Consequently, once the known facts of the tragedy were made public, the story then became one of rampant newsmaking, with Chief Arena and other members of his force, Mr. Teller and the county prosecutor, Walter E. Steele, all being beleaguered for more information.

The complaint being brought against Senator Kennedy stems from the fact that the accident was not reported immediately. The first report the police had came at 8:30 a.m. Saturday, when the submerged car was discovered by two young men. Bob Samuel, 21, and Joseph Capavella, 15, on their way back from an early morning fishing session on East Beach.

Scuba Team Called

Chief Arena went to the scene, found the car upside down in the water, and made several dives himself to try to determine whether there was anyone inside. Then he called for the Edgartown fire department scuba diving team, composed of John N. Farrar, Laurence Mercier and Jared Grant. Mr. Farrar dove down and found Miss Kopechne's body, dressed in black slacks and white blouse, in the rear seat. He secured a rope around her, and with the aid of the chief, got her out of the car and to the surface. The medical examiner, Dr. Donald R. Mills, came to the scene, and his examination revealed that she had died by drowning.

Meanwhile, the chief had initiated a check on the license plate number of the 1968 Oldsmobile, and had received word from the county communications center that it belonged to Senator Kennedy. When he called his station to have the senator notified of the accident, he was informed that the senator was then in the police station. This was about eight hours after the accident.

Chief Arena returned to Edgartown to confer with the senator, with Paul Markham of Boston, a former United States attorney, and with Joseph F. Gargan, the senator's cousin. Behind closed doors, the senator prepared an account of the accident, and then he and Mr. Markham and Mr. Gargan departed through a rear door of the town hall, refusing to answer inquiries from a reporter who was waiting there.

When he was questioned immediately after the departure of the senator, Chief Arena said that he had the statement but had agreed not to release it until Senator Kennedy had an opportunity to return to Hyannis and consult his lawyer. This was about 11:30 in the morning, but at about 3, when he still had not had word from the senator, he decided that he should release it. Shortly afterwards, Mr. Markham called to ask that it not be released for a while longer, but the chief told him that it had already been made public.

The statement was as follows:

"On July 18, 1969, at approximately 11:15 p.m. in Chappaquiddick, Martha's Vineyard, Mass., I was driving my car on Main street on my way to get the ferry back to Edgartown. I was unfamiliar with the road and turned right on Dike Road instead of bearing hard left on Main street.

Off the Side

"After proceeding for approximately half a mile on Dike Road, I descended a hill and came upon a narrow bridge, the car went off the side of the bridge. There was one passenger in the car with me, Miss Mary Jo Kopechne, a former secretary of my brother, Robert Kennedy.

"The car turned over and sank into the water and landed with the roof resting on the bottom. I attempted to open the door and window of the car but have no recollection of how I got out of the car.

"I came to the surface and then repeatedly dove down to the car in an attempt to see if the passenger was still in the car. I was unsuccessful in the attempt.

"I was exhausted and in a state of shock. I recall walking back to where my friends were eating. There was a car parked in front of the cottage and I climbed into the back seat. I then asked for someone to bring me back to Edgartown. I remember walking around for a period of time and then going back to my hotel room. When I fully realized what had happened this morning I immediately contacted the police."

The statement in its typed form left a blank for the last name of Miss Kopechne. Chief Arena said that Senator Kennedy had not been able to spell the name.

Until the senator had identified the young woman, the police, going by the contents of a handbag found in the car, had thought she might have been Rosemary Keough of Washington, D.C. Miss Keough, as was Miss Kopechne, was one of six young women staying at the Dunes for the weekend.

The rooms for the young women at the Dunes had been reserved by John B. Crimmins, long an aide of the Kennedy family, who had also made the boat reservations for the Kennedy car, according to a reservation slip found in the car.

Also found in the car was an eight-day lease on the Sidney K. Lawrence cottage on Wasque Road on Chappaquiddick, made out to Mr. Gargan. Neighbors of the cottage reported that there had been sounds of a party there on Friday night, and it was learned through members of the Kennedy staff in Washington that the party had been for David Hackett, a friend of the senator's brother, the late Sen. Robert F. Kennedy. However, another report from Washington had it that Mr. Hackett was not on the Island.

The senator himself had been staying at the Shiretown Inn while he was on the Island to take part in the Edgartown Yacht Club regatta. He sailed his Wianno Senior, Victura, in the Friday race and came in ninth.

Unclarified Point

The senator's statement made it unclear just when he returned to Edgartown after the accident. The last ferry crossed at midnight, and Jared Grant, the ferrymaster, reported that he was not on that trip. The management of Shiretown Inn refused to shed any light on the time the senator had returned there after the accident.

In seeking information on Miss Kopechne, the police telephoned the Dunes at about 8 o'clock Saturday morning. A check of the rooms showed that none of the six beds had been slept in the night before. Shortly after the call made by the police, a taxicab arrived at the Dunes and discharged several young women.

The unslept-in beds had led briefly to speculation as to the possibility that there might be more than one person missing, but a Gazette reporter who reached one of the young women at the Dunes by telephone learned that the five others were accounted for.

As late as 5 p.m. on Saturday Chief Arena had said that he would not bring charges against the senator, but about 10 p.m. he reconsidered and announced that he would bring a complaint of leaving the scene of an accident. Yesterday he made the comment to the reporters that the long gap of time between the accident and the senator's appearance at the police station made it imperative that he file the complaint.

But he said repeatedly that this was the only aspect of the case on which he intended to press charges.

As for the accident itself, he said that he did not see any evidence of negligence on the senator's part. Indeed, he emphasized the hazardous conditions of the bridge and its location.

The bridge crossing the channel between Cape Pogue Pond and Poucha Pond has a traveling service that is 10 feet six inches wide, bordered on either side by caplogs but no railing. The bridge itself is angled to the left from the road leading up to it. Markings found on the bridge Saturday morning indicated that the Kennedy car had continued in a straight path when it left the road, went onto the bridge and over the right side into the water.

No Warnings at Bridge

There are no signs or reflectors that would indicate to a motorist traveling at night that he is approaching a bridge, much less one that goes off at an angle.

Mrs. Pierre Malm, who is summering at the so-called Dike House, owned by Capt. Anthony A. Bettencourt, located only a short distance away from the bridge, told police the morning after the accident that she had heard a car passing her house between midnight and 1 a.m.

If the cottage the senator referred to in his statement was the Lawrence cottage leased by his cousin, he would have had to walk about a mile to reach it from the Dike. It has been remarked that to reach the cottage, he had to pass at least five other houses.

Chief Arena said Saturday that he believed that Senator Kennedy must have been in a state of shock, and the chief himself remarked that he found his own diving experience at the Dike Bridge, where the tidal current is strong, particularly exhausting. He also said that during the interview on Saturday morning, the senator had been cooperative in spite of the obvious strain he was under. His physician, Dr. Robert D. Watt, reported later that night that the senator had a "slight concussion in the back of the head".

When he was being bombarded with questions by reporters in front of the town hall yesterday, the chief revealed that he had asked the assistance of Lieut. George Killen, a state police detective attached to the district attorney's office, to assist him in the investigation of the case, but he indicated that the investigation is centering around the time period following the accident and before the senator appeared at the police station.

The body of Miss Kopechne was flown on Sunday to Plymouth, a small town just outside Wilkes Barre, Pa., for burial.

Active in Politics

Miss Kopechne, who was 28 years old, is the daughter of Mr. and Mrs. Joseph Kopechne of Berkeley Heights, N. J. She was a former campaign worker for the late Sen. Robert F. Kennedy, and had been active in politics since 1963. For the past year, she had been employed with Matt Reese and Associates, a political consultant based in Washington.

She was one of several members of Robert Kennedy's staff who had become occasional guests of Senator Kennedy on Cape Cod during the last year.

During her six years in Washington, she and three other women shared a home in Georgetown. One of her housemates, Miss Nancy Lyons, a member of Sen. Edward Kennedy's staff, was one of the six who had been invited to the Cape and to the Vineyard for the weekend.

The weekend ended tragically, and many persons on the Island, when they heard the news, expressed their dismay over yet another fateful incident in a series seemingly designed for a Greek tragedy afflicting the Kennedy family. As the weekend progressed, the dismay was intensified by the hungering newsmen, who, in the process of searching out every scrap of fact, turned a usually routine procedure, Chief Arena's walk across Main street yesterday to register the complaint, into a crowd scene worthy of Cecil B. DeMille.