MARION, Utah (AP) _ The suspect in the bombing of a Mormon Church building holed up for a third day today with 13 other people, six of them children, at the mountain compound where police killed his polygamist father-in-law, authorities said.

Addam Swapp vowed not to leave the home of John Singer until the polygamist leader is resurrected, a mediator said. Singer was killed by police trying to arrest him nine years ago today after he aimed a pistol at them.

Some 150 officers, including an FBI special weapons and tactics team, surrounded the 2.5-acre family compound in a mountainous ranching area about 60 miles northeast of Salt Lake City.

A half-mile away, in the parking lot of the bombed-out church, police set up three trailers as a command post.

Swapp and his family are ''heavily armed. They've got ammunition and they've dug bunkers around the main house,'' said Jim Soter, a Summit County commissioner and Marion town councilman.

Soter said he received a call a month ago from a man identifying himself as Swapp. ''He said only, 'You'll be destroyed,' and repeated it three times. I know Swapp is capable of destroying someone.''

Authorities said they hoped to bring a peaceful end to the siege, which began shortly after the explosion that damaged the community's Mormon chapel and recreation room about 3 a.m. Saturday. Within an hour, authorities went to the Singer home.

''Time is on our side,'' said Doug Bodrero, Utah's deputy public safety commissioner. ''We want to establish direct contact with them. We don't want to compromise.''

''We're here until it's resolved,'' said Public Safety Commissioner John Nielsen. ''There's no question that the device that was detonated in the building was not accidental. It was placed there.''

Nielsen said he spoke to Swapp late Saturday by telephone, but was unable to get an answer Sunday, when police telephoned every 15 minutes. Two FBI agents also knocked on the door of the Singer home Sunday but there was no response.

The calls were halted overnight, and the phone in the house apparently had been ''yanked out'' of the wall and would not ring today, said Cal Clegg, FBI special agent.

He said authorities' chief priority today was to re-establish contact with Swapp, possibly by sending a relative to persuade him to re-connect the telephone.

Singer had been excommunicated from the Church of Jesus Christ of Latter- day Saints, which outlawed polygamy in 1890. He once blamed the church for his legal problems, which including battles over authorities' efforts to place his children in state-approved schools.

A man claiming to be Swapp, who reportedly married two of Singer's daughters, called Salt Lake City television station KUTV and claimed responsibility for the bombing, the station reported Sunday night.

Roger Bates, a son-in-law of Singer, was asked by police to meet with the family and seek a peaceful solution. He left the home late Sunday.

''I told them what the police had to say,'' he said, adding those inside vowed to stay until Singer is resurrected.

Bates said Swapp told him he had bombed the church, and that ''is going to be one of the preceding events of the second coming of Christ.''

''They have weapons,'' Bates said. ''I don't know how many and I don't know how much. If the police go up there and storm the place, there will be bloodshed.''

''Yes, the family is prepared to die,'' he said.

Meantime, Bates said, ''the little children are playing games. They're trying to survive it the best way possible. At this point, they just want to be left alone.''

Bates also said the home was well-stocked with supplies.

In its report, KUTV quoted police as saying the caller could have been Swapp, based on details of the bombing he provided. The man said he had left a ''blood-red pole'' with nine feathers at the church, and that the pole was marked with symbols used by the Mormon priesthood.

Police earlier said a spear had been left with a note attached bearing Singer's name and Jan. 18, 1979, when Singer was killed.

The caller vowed no compromise and said the bombing was in retaliation for what he said was the Mormon Church's role in Singer's death.

''Now his blood cries back from the ground for vengeance from a just God,'' he said. ''The Lord has given a commandment that we should stand and fight manfully, and we have been assured that the Lord will fight our battles.''

Nielsen would not discuss the report, except to refer to it as ''an alleged call'' from Swapp.

Singer had defied authorities by keeping his children out of school, saying that would expose the children to sex, drugs and textbooks teaching racial equality.

Swapp wrote a four-page letter sent Sept. 14 to Mormon leaders, former school officials, judges and others threatening ''the wrath of a just God'' for their alleged roles in Singer's death, the Deseret News reported Sunday.

One of Singer's two widows, Vickie Singer, who was among those inside the compound, said the bombing was ''symbolic of what is coming.''

''We are not going to make peace with them,'' she told the Deseret News. ''We will not surrender. We have gone beyond talk. We are going to battle.

''Yes, there will be death, killing.''