DALLAS (CBSDFW.COM) – Dallas police say they are investigating a string of assaults and robberies in December that involved a popular dating app as hate crimes.

According to police, four victims in December were lured to a vacant apartment in the 8000 block of Chariot Street and were then robbed and beaten. The victims thought they were meeting someone they met on the dating app “Grindr,” which is geared towards gay and bisexual men.

Police believe the crimes were motivated on the victims’ sexual orientations, which is why they are being investigated as hate crimes.

One of the robberies has been reclassified as a sexual assault, according to police on Saturday.

Police say one person is in custody in relation to the crimes, but they are working to find additional suspects.

Police are asking anyone that has information on these crimes to call 214.671.3584 or Crime Stoppers at 214.373.8477.