Authorities in Texas have made an arrest in a shooting at an off-campus college party in Greenville over the weekend that left two dead and a dozen injured. Hunt County Sheriff Randy Meeks said tips led to the arrest of Brandon Gonzales on Monday. The 23-year-old is charged with capital murder of multiple persons and his bond is set at $1 million, reports CBS Dallas/Fort Worth.

Meeks said Gonzales is "cooperating" with police and admitted that he was at the party, but has not admitted to being the shooter. He showed up to work this morning at a local auto dealership where he's a mechanic, Meeks said.

"We kept pushing and pushing until we got one tip that led to another, that led to another, and we were able to come up with the identity of the shooter," Meeks said.

Get Breaking News Delivered to Your Inbox

So far, there's no word on a motive. Investigators believe Gonzales acted alone.

Brandon Gonzales CBS Dallas/Fort Worth

Saturday night's shooting occurred just after midnight at The Party Venue on U.S. Highway 380, and involved students from Texas A&M Commerce, about 60 miles northeast of Dallas, CBS DFW reported. However, the event was not sanctioned by the school, according to officials.

Meeks said 12 people were injured, including six who were shot. Investigators told CBS News the gunman entered the building through a back door and his first victim may have been his intended target. The shooter used a handgun.

Sheriff's deputies were already on scene responding to reports of illegal parking when gunfire erupted. Meeks said it is believed there were over 750 people at the party.

Dramatic cellphone video showed the aftermath of the shooting — wounded partygoers laid out on the floor as others desperately tried to help them, CBS News' Mireya Villareal reported.

"It's just kinda sad knowing that we were here coming to like celebrate something and then something like this happens, but I guess it's just the world that we live in, so," said Ciara Vital, who was at the party. "It kind of hurts but it's the world that we live in now."

The two victims were identified as Kevin Berry Jr. of Dallas and Byron Cravens Jr. of Arlington, both 23, the station reports. Texas A&M-Commerce confirmed four of the people injured were students who were treated and released.

On Sunday night, gunfire erupted after a vigil for one of the two people killed, CBS DFW reported. There were no reports of injuries, but a vehicle for one TV station was struck by bullets.