With public pressure intensifying to find the killers of a Roman Catholic bishop who spoke out against wartime military abuses, a U.S. team of investigators headed here to help in the investigation Thursday.

After a funeral Mass for Bishop Juan Gerardi Conedera punctuated by cries for justice, U.S. Ambassador Donald Planty said Wednesday that FBI experts were on their way. Local newspapers Thursday reported that the first one had arrived.The Clinton administration offered the U.S. help earlier this week, as demands grew for President Alvaro Arzu's government to solve the crime.

Gerardi was killed Sunday night by unknown attackers, who crushed his skull with a jagged concrete block in the garage of his parish home. Two days before, he had released a report detailing military abuses during Guatemala's 36-year civil war, which ended with a 1996 peace accord.

On Monday, church leaders gave the Arzu government 72 hours to find the killers - a deadline missed Wednesday as more than 10,000 mourners filled the Metropolitan Cathedral.

Gerardi was eulogized as an advocate for Guatemala's impoverished Indian majority.

"He fought for reconciliation, for authentic peace," said Bishop Gerardo Flores of northern Vera-paz. "That is why they wanted to silence his voice."

"Justice! Justice!" some mourners cried as Gerardi's casket was entombed in the cathedral crypt.

Gerardi, 75, knew about political violence. He closed his diocese in the mostly Indian Quiche province at the height of civil conflict, after military-backed civilian patrols targeted his priests and workers.

Most believe his killing was a warning not to delve into past wrongdoing by the military, which the report blamed for nearly 80 percent of the 200,000 wartime killings and disappearances.