The police report on 21 Savage's arrest, which TMZ has obtained, has complicated what we know of the British born rapper being taken in by ICE on Super Bowl Sunday.

According to the docs, 21 Savage was in a red Dodge Challenger that cops say drove across the sidewalk in an attempt to get onto another street. The cops pulled the car over and ATF agents -- who were also on scene -- ordered 21 to stop and throw the keys out the window. According to the report, 21 threw the keys out, along with a bottle containing an unknown substance.

21 got out of the car and was immediately handcuffed and taken away by ATF. The police report has an evidence inventory section and lists the firearm -- the fully-loaded Glock -- as connected to 21 Savage. The gun was found in the glove box in the Dodge 21 was driving. It had an extended magazine.

In the center console, there was a styrofoam cup containing an unknown substance. As for the bottle that was thrown out of the car ... cops don't say what was in it but it was taken into evidence.

The documents also confirm reports that 21's cousin Young Nudy -- who was in another car -- was the actual target of the ATF agents

While there were several agencies present during the incident, including the DeKalb K-9 Unit, Vice Unit, Narcotics Unit, ATF, Georgia State Patrol, and the DeKalb 90 Unit, ICE is not mentioned on the initial police report.

This suggests they were called after the officers on the scene ran Savage's name and found out that he was an illegal immigrant. 

Savage is in the custody of ICE, which has been initiating deportation proceedings. This new information suggests his lawyers have their work cut out in their attempt to keep him in the U.S.

Update: 21's lawyer Alex Spiro denies the weapon and the car were his clients:

"ICE has confirmed he was targeted for immigration enforcement and nothing more. He was never arrested by the police, and some other individual's firearm and vehicle is not our concern here."