EL PASO, Texas (KTSM) – Two brothers who were arrested last week on suspicion of firing guns on an El Paso freeway last month and posting about it on social media allegedly told officers they were celebrating their father’s birthday, court documents say.

The arrest affidavits of Ruben Macias, 23, and Josue Macias, 21, contain details on how the El Paso Police Department’s Gang Unit tracked down the suspects and the duo’s explanation of their actions in the viral video.

Both men were arrested on Nov. 25 in the 5300 block of Beautonne after officers executed a search warrant and found guns and drugs, police said.

According to an arrest affidavit, Gang Unit officers became aware of the viral video on Nov. 24, began to scan social media and saw different people posted a photo of the possible suspects. Investigators were able to identify the Macias brothers as the primary suspects.

Officers began to watch the brothers’ home and saw both men arrive at the house and exit a 2016 Nissan Sentra, which had the same interior as shown in the video, the affidavit said.

When the brothers later left the house, officers saw Josue Macias commit a stop-sign violation and pulled the vehicle over to arrest him for the traffic violation, the affidavit said.

Josue Macias allegedly confirmed to officers that he and his brother were the ones in the video firing guns while driving on U.S. 54 North between Transmountain and Sean Haggerty. According to the affidavit, he told officers they were celebrating their father’s birthday on Nov. 17 between midnight and 1 a.m. by shooting the guns up in the air “as they do in Mexico,” the affidavit said.

Josue Macias told officers they each have their own gun which was at their home in the side of two different couches. He also told officers that Ruben Macias recorded the video and uploaded it to Instagram where someone else stole it and later reposted to social media.