Authorities in Detroit are hunting a group of men who gang-raped two women in separate crimes last week. Police have yet to make an arrest in either case, reports said Sunday.

In both incidents, a group of men stripped and robbed a young couple at gunpoint and then raped the woman while forcing the man to watch, the Associated Press reported. The attacks occurred within two hours of each other on Detroit’s northwest side. Authorities said six men participated in the first attack, which occurred Thursday.

“One of the suspects produced a gun, pointed it at both victims and advised them to go to an alley. Both victims complied. They were forced to the ground. The male victim was forced to watch the female victim get sexually assaulted. Their clothes were taken,” Police Sgt. Cassandra Lewis told the Associated Press.

The second assault unfolded in a similar manner, but with four assailants, police said. Both rapes occurred on McNichols Road, WDIV-TV in Detroit reported. Authorities said at least one suspect probably took part in both assaults.

Police said the attackers might have been spotted near a blue Ford-model car before or after the assaults. They purportedly fled the scene of the second attack on foot. Detroit authorities released sketches of three men suspected in the incidents, the Detroit News reported.

Authorities are working to assess possible connections between the two attacks that occurred last week and a separate rape that occurred in Detroit on July 11. In that incident, a woman, 18, was robbed and raped while her 21-year-old male companion was forced to watch.