A Texas law that allows local law enforcement to arrest migrants suspected of illegally crossing the border has several leaders in the Rio Grande Valley wondering how they’ll enforce it.

Senate Bill 4 was signed into law last month, and the Justice Department filed a lawsuit against it on Jan. 3.

Hidalgo County District Attorney Toribio “Terry” Palacios said his office is waiting for a ruling to decide how to proceed.

Court records don’t list a hearing date for the lawsuit as of Tuesday evening. 

READ MORE: Justice Department sues Texas over law that would let police arrest migrants who enter US illegally

“We don't know what is going to happen at this point, so let's see what the lawsuit comes out on the federal side,” Palacios said.

The Mission Police Department said if the law takes effect, they will comply — but they are looking to the state for guidance on how to enforce it.

Mission assistant police Chief Teodoro Rodriguez said an influx in arrests could be a challenge for his department.

U.S. Rep. Monica De La Cruz, R-McAllen, says Senate Bill 4 is necessary to secure the border, but she understands the concerns from local law enforcement.

“Local law enforcement should not be doing the federal government's job,” De La Cruz said

Senate Bill 4 also requires a judge to order migrants to "return" to Mexico if they're convicted.

Charges could be dropped if a migrant agrees to return on their own.

Channel 5 News asked Palacios which judges would preside over those cases. 

“That is what the law is not clear about,” Palacios said. "That's why we are waiting for the pending litigation so we are going to know how to execute it."

Watch the video above for the full story.