One moment, a man is seen running through a parking lot near Houston as an unmarked black SUV appears to pursue him from behind. Seconds later, the man is seen lying on the ground.

Exactly what happened in between remains a mystery as authorities investigate the circumstances. In surveillance video obtained by CNN, the moment of impact is blocked by a parked pickup truck.

The incident happened just days after an ICE-involved shooting in New York City in which agents shot and wounded a driver while his 5-year-old child was in the back seat. ICE said the agents thought their lives were in danger after the man refused lawful orders to exit the vehicle.

Here’s what we know about what happened in Houston:

What led up to the pursuit?

Federal agents were trying to conduct a vehicle stop Saturday when two men got out of a white pickup truck and sprinted away, an ICE spokesperson said.

The target of the operation, undocumented immigrant Jose Mendoza-Cervantes, bolted and hasn’t been seen since, ICE said. The other man, later identified as Miguel Parra-Hernandez, is an undocumented immigrant from Mexico, ICE said.

What does the surveillance footage show?

Parra-Hernandez jumped out of the vehicle and ran into a parking lot, surveillance footage shows.

The video appears to show an unmarked black SUV accelerating into the parking lot. Then Parra-Hernandez disappears from view behind a parked pickup truck, which blocks the moment of impact.

The parked pickup truck drives away, revealing Parra-Hernandez lying on the ground and the unmarked SUV stopped in front of him.

What does his attorney say?

Parra-Hernandez has two broken legs and was expected to undergo surgery, his attorney Kim Bruno told CNN.

She said her client has lived in the US since he was a child.

“He’s been here for 34 years. He’s a good guy, nothing on his record at all,” Bruno said. “No encounters or apprehensions with immigration, ever. He’s been here since he was 14.”

What do authorities say happened?

The ICE spokesperson said Parra-Hernandez is an undocumented immigrant from Mexico who “ran in front of an ICE vehicle.”

ICE said it “immediately contacted EMS and provided aid” to Parra-Hernandez, who had non-life-threatening injuries and was in stable condition.

The other man, Mendoza-Cervantes, remains unaccounted for. ICE described him as a “public safety threat” with several prior arrests for driving under the influence and for unlawful possession of a firearm.

One of the ICE agents was trying to box in Parra-Hernandez when he was struck, said Maj. Anthony McConnell of the Harris County Sheriff’s Office.

CNN has reached out to ICE for comment on the surveillance footage.

What will happen next?

The Harris County Sheriff’s Office is leading the investigation, with assistance from the Harris County District Attorney’s Office.

Authorities are trying to get more surveillance footage from the scene, said McConnell, who leads the sheriff’s office’s special investigations bureau.

CNN has reached out to the sheriff’s office and the district attorney for additional information.

Is ICE changing its rules on vehicle stops?

As CNN reported earlier this month, ICE officers will be allowed to conduct vehicle stops only if they have completed related training courses and must ensure vehicles used for stops are equipped with lights and sirens, according to new internal guidance reviewed by CNN.

The agency came under heightened scrutiny over vehicle stops after two immigrants, Lorenzo Salgado Araujo in Houston and Joan Sebastian Durán Guerrero in Biddeford, Maine, were fatally shot by ICE officers in July in two separate incidents.