DETROIT » Police in Detroit are searching for men who allegedly robbed two young couples at gunpoint in separate attacks two hours apart and gang-raped the women while forcing the male victims to watch.

The attacks happened Thursday night along a major street on Detroit’s northwest side, police said. In each case, the couples were out walking when their attackers, armed with handguns, approached them.

"It’s horrifying," police Deputy Chief Charles Fitzgerald told reporters Friday.

Six men took part in the first attack and all six of them raped the woman, Fitzgerald said. There had been no arrests as of Sunday afternoon, police Sgt. Cassandra Lewis told The Associated Press.

"One of the suspects produced a gun, pointed it at both victims and advised them to go to an alley," Fitzgerald said. "Both victims complied. They were forced to the ground. The male victim was forced to watch the female victim get sexually assaulted. Their clothing was taken."

The second attack happened about two hours later and was almost identical to the first, except this time there were only four men who took part, the deputy chief said. Like in the first attack, they walked up to a young couple and one of them showed his handgun and ordered the couple into an alley. The suspects took the couple’s clothes and raped the woman, he said.

He said they fled on foot and were seen near a blue Ford SUV.

Police released sketches of three of the suspects, including one who they are confident took part in both attacks.

Investigators are trying to determine if the attacks are linked to a July 11 attack in the same area in which two men robbed a couple at gunpoint and raped the woman. They haven’t definitively connected it with the others, Lewis told The Detroit News.

Fitzgerald said residents of the area need to be cautious.

"Use your sixth sense," he said. "If something doesn’t feel right, run to a nearby store or something."