BEIRUT, Lebanon (AP) _ The military prosecutor has ordered a suspect in the bombing of the American University of Beirut held in solitary confinement while he is interrogated and police hunt for accomplices, police said Thursday.

The order was issued Wednesday for Jihad Khalil, 28, according to a police spokesman, who cannot be named according to regulations.

Khalil, a Shiite Muslim from south Lebanon, turned himself in last weekend and told police he had killed his sister, Hayat, 24, to ''avenge family honor'' following a dispute over a moral matter. The sister's body had been retrieved from the sea a few days earlier.

But during interrogation, Khalil confessed to a role in the bombing, the spokesman said. As-Safir, a leftist newspaper, said Ms. Hayat had driven the car full of explosives that blew up at the university, and that Khalil helped set off the explosion.

One man was killed and eight people were wounded in the car bomb explosion at the university campus on Nov. 7. The administration building and the library were severely damaged.

The independent An-Nahar newspaper said Thursday that Khalil was one of four accomplices in the bombing. It did not name the others, but said two of them had served time in Israeli detention centers in south Lebanon.

As-Safir, a leftist newspaper with good connections to the security apparatus, on Thursday identified two of the accomplices as Pierre Khoury, a Christian who allegedly rigged the car with explosives, and Hussein Abdul- Nabi, a Shiite Muslin in the South Lebanon Army.

The militia is trained, armed and financed by Israel. It helps patrol Israel's self-styled security zone in south Lebanon to prevent attacks in Israel's border region.

Abdul-Nabi has topped the government's wanted list for years in connection with acts of sabotage, assassinations and robberies.

On Wednesday, As-Safir said that Hayat Khalil, a former student at the university, drove a bomb-laden Volkswagen to the campus and parked it outside College Hall, one of the oldest buildings on the 125-year-old campus.

The report said Khoury and Jihad Khalil pressed two detonators that set off the explosives.

As-Safir said Khoury had promised Khalil and his sister $500,000, saying Israel was financing the operation. When the woman pressed for a first payment during a meeting at a Beirut hotel after the bombing, he shot her and dumped her body into the sea, the report said.

The newspaper said Khoury then persuaded Jihad Khalil to turn himself in and tell police he killed his sister over a moral issue. But Khalil broke down under interrogation, according to As-Safir.