Authorities examining last week's subway train firebombing in lower Manhattan have located new eyewitnesses who saw the badly burned suspect fleeing in the streets and aboard another train and have found new evidence at his home in New Jersey, including videotapes on bombmaking, investigators said Saturday.

The new witnesses and other evidence appeared to solidify an already strong case against Edward J. Leary, a 49-year-old unemployed computer expert, who is charged with attempted mass murder in a firebombing that injured scores of riders aboard a No. 4 train at the Fulton Street station Wednesday.Investigators have charged that Leary, who lost his job at Merrill Lynch last January and had large real estate debts, planned a terrifying campaign of subway bombings to extort money from the city. They said his first bomb burned two teenagers in Harlem on Dec. 15, while the second exploded in his face as he tried to set a timing device so it would go off in an East River tunnel.

Leary, who suffered third-degree burns over 40 percent of his body, remained in critical condition Saturday at the burn unit of New York Hospital-Cornell Medical Center. Also in critical condition there were two victims - Reufield Edey, 60, who suffered deep burns over 65 percent of his body, and Brenda Dowdell, 40, with burns over 35 percent of her body.

Manhattan District Attorney Robert Morgenthau said Saturday that the firebombing case would be presented to a grand jury Tuesday and that Leary would be arraigned in the hospital as soon as his condition permitted a bedside proceeding.

Leary's lawyer, Stephen J. Murphy, visited his client Saturday and said afterward that his condition appeared to be improving. But he said Leary was heavily tranquilized with morphine for pain, sometimes faded in and out of consciousness, and appeared to have impaired hearing.

"He was sleeping when I arrived," Murphy said. "He awoke to my presence and I talked with him. But it was difficult to ascertain whether he was really hearing and understanding what I was saying. He's drugged, so one minute he can answer and a few minutes later he seems off."

Murphy said much of Leary's lower face was burned, especially around the lips, and his legs and buttocks were severely burned. Ointment was spread around the facial burns, but his head was not swathed in bandages, he said.

Murphy noted that Leary's wife, Marguerite E. Shaller, had visited her husband Friday and was being "very supportive."