A man holding a 20-gauge shotgun in his hands and carrying a canvas banfoleer full of shotgun shells over his shoulder stormed into the Forest Haven home for the District's mentally retarded yesterday afternoon and terrorized residents and employes with a shooting spree that left seven persons injured.

Linwood Goodwyn, a 44-year-old form service worker at Forest Haven who was known as a quiet and gentleman, was arrested by police shortly after the incident and charged with assault with intent to kill.

Police investigators said last night they could determine no motive for the shootings, but they said it appeared the suspect was "looking for someone" when he entered the suburban Laurel center.

The injured - two residents and five employes at Forest Haven - all suffered minor shotgun wounds, accurding to officials at the various area hospitals where they were treated. All seven had been released by early last night.

U.S. Park Police officials who arrested Goodwyn and administrators and employes at Forest Haven offered the following account of how the incident occured:

Shortly after 12:20 p.m., the man entered the Forest Haven dining area building by the side door. A 20-gauge shotgun was in his hands, a canvas bandoleer with six shotgun shells was draped over his shoulder.

A cook in the Forest Haven cafeteria spotted the man as he entered the building. She said she attempted to talk to him, "but he rushed right by."

The man ran upstairs to the eating room and flashed his shotgun, but did not shoot. The luncheon diners - residents and employes - scattered out of the room, some running downstairs.

The man then ran downstairs and, as he left the building, fired two or three shots into a room that contained 25 or 30 people. The seven residents and employes apparently were struck by those shots.

The man then feld in a blue and white Chevrolet Nova. He was pursued by Gerald T. Semple, a guard at Forest Haven. Semple radioed the U.S. Park Police station at Greenbelt to inform them that the man was driving down Rte. 198 toward the Baltimore-Washington Parkway.

U.S. Park Policeman Gregory A. Lehman piked up the call on the parkway. As he approached Forest Haven, Lehman spotted the Nova travelling in the other direction down Rte. 198. Lehman turned around and pursued the car for six miles.

At Rte. 198 and the parkway, according to Lehman, the Nova pulled over to the side of the roadway. Lehman got out of his squad car and approached the man's car. Lehman said he shouted "Get out of the vehicle" three times. Finally, Linwood Goodwyn emerged from the Nova, unarmed, Lehman said.

Lehman handcuffed Goodwyn and took him to the federal lock-up next to the U.S. Magistrate's office at the Presidential Building in Hyattsville.

There, Goodwyn appeared at an arraignment hearing before U.S. Magistrate George Burgess. He was charged on one count of assault with intent to kill. Bond was set at $50,000.

Back at Forest Haven, which houses about 1,000 mentally retarded District residents, administrators and employes were attempting to calm down scores of people who, in the words of one employe, had been "scared, shocked and frightened to death." Forest Haven officials said one cook at the facility, who had a heart ailment, suffered a heart attack about two hours after the incident.

Goodwyn was quivering and sobbing as U.S. marshals led him from the detention cell on the fourth floor of the federal facility in Hyattsville to a car that would take him to an overnight lock-up at the Prince George's County jail in Upper Marlboro.

"I've been depressed," he said, looking down at his handcuffed hands. "I've been so depressed. I have loved ones . . . three children . . . a wife."

The frail suspect, wearing blue jeans, a plaid shirt and tan leather jacket, was still crying as he walked down a long basement corridor to the police car.

Federal investigators and employes at Forest Haven confirmed that Goodwyn has a wife and three children.

Several of Goodwyn's neighbors in the garden apartment building where he lived at 14111 Bramble Lane in Laurel said they believed Goodwyn lived there with a woman. None of the neighbors knew the woman's name. They said there were no children living in Goodwyn's apartment.

One neighbor, Charles Parsons, described Goodwyn as a "super friendly, polite and helpful man." Said Parsons: "He had a CB radio and once he came over and told me that if I started picking up his CB on my television set to let him know and he would take care of it."

Another neighbor, Gary Hughes, recalled that Goodwyn used to "bet some of the kids a quater on the Red-skins football games and then make sure the kids won."

Goodwyn's coworkers and superiors at Forest Haven offered similar appraisals. Jefferson McAltine, the D.C. mental health administrator, said Goodwyn was "a very controlled" person and an "engaging man" who did not exhibit anger or depression.

The officer who arrested Goodwyn, U.S. Park policeman Gregory Lehman, said Goodwyn appeared "incoherent and dazed" in the squad car as Lehman took him to the detention cell in Hyattsville. Lehman said Goodwyn did not say a word during that trip.

Those injured during the shooting spree were: Nathaniel Jamison, 25, and Willie Rice, 26, both residents of Forest Haven; and Forest Haven employes Conway Jones, 21, of 635 50th Street SE; William Diggs, 37, of 2619 Southern Ave., Oxon Hill Dwayne Kee of Rhode Island Ave., NE; and Dewitt Stith, whose address could not be determined.