A proposed sanctuary city bill had its first committee hearing early Thursday morning. The bill, spearhead by state Sen. Charles Perry, R-Lubbock, would penalize local government entities whose law enforcement officials do not cooperate with federal immigration investigations.

The sanctuary city debate recently received publicity when Travis County Sheriff Sally Hernandez made good on her campaign promise to not detain undocumented individuals for federal immigration law enforcement. Hernandez said this would allow undocumented individuals to build trust with law enforcement and be able to report crimes without fear of deportation. Gov. Greg Abboott responded by pulling $1.5 million in state support money.

Here are four other things to know about the sanctuary city bill and subsequent hearing that occurred Thursday morning:

1. Perry sponsored the bill with four other Republican senators, who sit on the State Affairs Committee, the group tasked with reviewing the legislation. Other authors include Sen. Brian Birdwell, R-Granbury; Sen. Craig Estes, R-Wichita Falls; Vice Chairman Sen. Brian Hughes, R-Mineola; and Sen. Charles Schwertner, R-Georgetown. Democrats on the committee delivered the most questions, indicating this bill may divide the Senate along partisan lines.

The legislation is moving forward because Abbott declared the issue an emergency item in his State of the State address Tuesday. He said this was the session that Texas would end sanctuary cities.

2. Hundreds lined the hallways of the statehouse to watch the proceedings and testify. At the beginning of public testimony, Chairwoman Sen. Joan Huffman, R-Houston, said 458 individuals had signed up to testify on the matter. Each person giving testimony was limited to two minutes of speaking. That amounts to more than 15 hours of scheduled testimony.

Less than a minute into the proceedings, protestors started singing verses of "Which Side Are You On" and were immediately ejected. Huffman issued several warnings throughout the morning, threatening to clear the gallery if protests persisted. At one point, a woman yelled, "Greg Abbott is a fascist" to a large round of cheers and applause.

3. There is still no clear definition of a "sanctuary city." Although Abbott stated his clear intention to eliminate sanctuary cities, many lawmakers are left with a number of questions. Sen. Juddith Zaffrini, D-Laredo, questioned Perry on his definition of a sanctuary city.

"There is no specific definition," Perry said.

Most identify sanctuary cities as those whose law enforcement officials fail to comply with federal immigration authorities after arresting undocumented individuals. However, the degree of compliance is often the question.

4. Senators are hesitant that Senate Bill 4 could lead to racial profiling. Sen. Sylvia Garcia, D-Houston, asked a number of questions about how the bill would be implemented and if it could be rolled out in any way that would target individuals purely based on their perceived immigration status. Sen. Jose Menendez, D-San Antonio, asked similar questions, expressing concern the bill could turn down the same path an Arizona immigration law did several years ago. This Arizona law had portions struck down by the Supreme Court.

Perry said the Texas bill would only further codify federal immigration law and would be applied equally and without prejudice.

Read the full text of the bill here.