The babysitter who was caring for 1-year-old Amani Renee Robinson when she died at her family's Rockville home Thursday is the same man who had been baby-sitting for a 2-year-old Rockville boy when he died in 1997, officials said yesterday.

The 30-year-old Rockville man, who has not been charged in either case, surrendered to Montgomery County police Thursday on an unrelated charge and was being held last night in the Montgomery County Detention Center.

Authorities said that the man is being investigated in connection with both deaths.

Amani was pronounced dead at Shady Grove Adventist Hospital on Thursday morning. A caller told a 911 dispatcher that the little girl had been found dead in the bathtub. Sources said that there was no indication that the baby had drowned but that she had a bruise on her head. The Maryland medical examiner's office in Baltimore said yesterday that an autopsy was performed on the child but that the cause and manner of the child's death are pending.

Few details about the 1997 death could be learned yesterday. Authorities identified the child as Andre Wentworth, whose family lived on Viers Mills Road in Rockville.

Andre's death, on Jan. 31, 1997, was ruled a homicide, a source close to the investigation said, but prosecutors did not file any charges because there were several people present when the baby died.

"That the child was killed was not in dispute," the source said. "What was unsettled was who was the agent in the death."

In an interview yesterday, Amani's mother, Amy Hogan, said she had met the man in the Lincoln Park neighborhood, and he later became her boyfriend. On the night before her daughter died, Hogan said, the man came to her home, saying his mother had died. She stayed up late consoling him, she said.

When she awoke early Thursday morning, Hogan said, the man offered to care for Amani and a second daughter, 4, that day. Hogan said she bathed both children, dressed them and left for her temporary job as secretary shortly after 8 a.m.

Less than an hour later, Hogan said, she received a phone call saying her daughter had been taken by ambulance to Shady Grove Adventist Hospital. Paramedics had been summoned to her residence in the unit block of Moore Drive about 8:44 a.m. after a report of a drowning. Paramedics said they found Amani lying on the living room floor and that no one had attempted cardiopulmonary resuscitation on the child.

Hogan said she was told shortly after she arrived at the hospital that her daughter had died. She said that the man, who rode with Amani to the hospital, had already left.

"He told me his mother died. . . . Why would you lie about your mother dying?" Hogan said, explaining that she later learned that the woman was not dead.

"I got both my girls dressed in the morning. I don't know why he would be putting her in the tub or why he would have left her in the tub," she said, adding, "I don't know. . . . There's just so many unanswered questions."

Court records show that the man was arrested on a warrant charging him with theft over $300. The summons for the charge was issued on July 21, records show.

Records also show that the man has been arrested in Maryland on various charges, including theft under $300 and drug possession, but that in each instance the charges were dropped.

Hogan said that she did not know that the man had ever been arrested.

In an unrelated case, Anne Arundel County police are still investigating the suspicious death of a child whose body was found in woods near Baltimore-Washington International Airport last week.

Police believe the body is likely that of 3-year-old Z'aira Tri'ann Marshall. Detectives were led to the body Aug. 22 by the child's father, Richard Lee Marshall, of Severn, who told them she had died suddenly in his home in December. Z'aira's mother, who lives in New Jersey, did not report her missing until this month.

Investigators said that no evidence so far points to homicide and that no charges have been filed.

Staff writers Katherine Shaver and Amy Argetsinger and researcher Bobbye Pratt contributed to this report.