Thousands of Texans went to the capitol on Thursday to join the debate over sanctuary cities, including San Antonio's police chief.

In front of a Texas senate committee, San Antonio Police Chief William McManus joined Austin’s police chief in stating his opposition to Senate Bill 4.

“In short, San Antonio is not a sanctuary city. However, I have some serious concerns,” Chief McManus said.

McManus told state senators that SAPD is understaffed as it is. He estimated that it would take at least a year and it would be very expensive to train the entire department on enforcing immigration laws.

“This bill usurps the authority of police chiefs to direct their departments,” he said. “We simply do not have the capacity to handle immigration laws as well as enforcing the laws of the penal code."

One of the sponsors of S.B. 4, Senator Charles Perry from Lubbock, said in his opening statement that the bill would not turn local law enforcement into immigration agents.

“This is simply not true,” State Senator Perry said. “Nowhere in the bill does it instruct officers to demand papers. Nowhere in the bill does it allow officers to stop a person solely to enforce federal immigration law.”

If S.B. 4 became law, cities, police departments, and colleges could not make laws or policies to stop officers from asking someone's immigration status. Victims of crime who are in the country illegally would be protected.

S.B. 4 would also force county jails to give up undocumented immigrants wanted by the feds. While it's not clear what college police would have to do, Carmen De Luna-Jones, who works with undocumented students at Alamo Colleges, said that it’s adding to fear and anxiety for students protected from deportation by an executive order passed under former President Barack Obama.

“If something were to happen to me on the campus and I have to report something, how comfortable am I going to be able to do that if I know that campus police may be asking me for my documents,” said De Luna-Jones of student fears.

S.B. 4 would have to make it out of the senate and get house approval before it could become law.