The Justice Department yesterday began a preliminary investigation of the police shooting last week of seven black religious zealots in Memphis to determine whether any civil rights laws were violated.

The members of a tiny, unnamed cult, who apparently believed police were the "anti-Christ," had captured a white policeman and beat him to death, authorities said. Police stormed the house after it became clear that the officer was dead, shooting all seven of the men in the head, authorities said.

Twelve shots were fired at the six-man police team during a 20-minute assault of the pitch-dark, tear gas-shrouded house, Memphis authorities said at a news conference yesterday. The officers returned fire with 80 rounds from M16 automatic rifles and 12-gauge shotguns, police said.

Police said yesterday that they believed the cult members were heavily armed during the assault. After the assault, they found only two .38-cal. revolvers and about two dozen rounds of ammunition. The guns were taken from captured officer R.S. Hester, 34, and his partner, who managed to flee, police said.

"We believe that the weapons probably changed hands several times during the assault," police Director John Holt said yesterday. "Three had guns in hand when shot. One had a knife in his hand."

"I have relived these hours many times," Holt said. "I don't know of a thing we could have done different. We had spent 30 hours trying to get these people to talk with us, surrender, cooperate . . . all of which had been totally futile."

None of the victims had powder burns on the skin, indicating that they were shot from beyond two feet, Shelby County Medical Examiner Jerry Francisco said yesterday in a telephone interview. "We did not find any wounds that fit into the vernacular of execution-type wounds," he said.

Five men were shot during the assault before Hester's body was found by the front door, his hands bound behind him, police said. He had been dead 12 to 24 hours, Francisco said.

"Many people in the black community feel it's an unwritten law that if a police officer is harmed--and certainly if he is killed--there will be no survivors," Maxine Smith, executive secretary of the Memphis NAACP, said. "The police have done nothing to alleviate those suspicions. Those who know what really happened are dead.

"I don't doubt some life would have been lost in the affair no matter how it was handled," she said. "But the big question that casts a shadow is, was it necessary for eight people to be killed?"

According to neighbors and seven cult members who ran from the home of Lindberg Sanders, 49, after Hester was captured on Jan. 11, those who remained were heavily armed, a police spokesman said. "Throughout the entire assault, we were under the impression they were much better armed," he said.

Modeled partly after Jamaica's Rastafarians, Sanders' Bible-reading, wine-drinking cult avoided water, pork and hats, smoked marijuana as a sacred herb and said they believed police were agents of the devil, Holt said.

Sanders predicted that the world would end Monday, Jan. 10. When this failed to happen, he became agitated, police said. On Tuesday, Hester was taken hostage while making a routine house call.

Sanders' followers numbered 25. He wanted a Memphis radio station to provide live coverage for Hester's execution, police said.

Sanders "wanted the people of Memphis to hear when he put the officer's lights out," Holt said.