SAN MARCOS, Texas (KXAN) — Three people were arrested on charges of kidnapping and smuggling undocumented immigrants, according to a news release from the San Marcos Police Department.

Mason Castillo, Robert Cruz and Jeremiah Villarreal are facing charges including Smuggling of Persons, Engaging in Organized Criminal Activity, Aggravated Robbery and Aggravated Kidnapping for Ransom/Reward, according to police.

SMPD said it was the sole law enforcement agency investigating the crimes beginning in August, when a group of immigrants were smuggled from Mexico to Austin and kidnapped by force in transit to their destination.

“The investigation took about four weeks until sufficient probable cause was developed to issue arrest warrants on all three suspects and for the issuance of multiple search warrants,” said San Marcos Police Detective, Casey Tennant, in the news release.

The three men are accused of holding at least 10 undocumented immigrants until they paid them several thousand dollars in cash, according to police. The victims told detectives they were held at a home in San Marcos but didn’t know exactly where. After looking through video footage of a business in San Marcos and mapping out a radius that correlated with the time traveled to reach the home, detectives were able to determine where the victims were held, the release said.

Furthermore, police were also able to identify suspects through information provided by the victims, along with surveillance video and digital forensics from a cellphone, the release said. It was later determined Castillo and Villarreal had a criminal history for smuggling of persons, SMPD said.

During the early morning hours of Sept. 7, SMPD officers served warrants at homes located on Academy Street, Hillyer Street and Lazy Lane, according to police. Several law enforcement agencies helped SMPD conduct this operation safely, including the Hays County SWAT, Department of Public Safety SWAT, Bastrop County SWAT, New Braunfels SWAT, and Texas State University Police, the release said.

“Due to the threat to the safety of the potential victims being held against their will and the multiple locations being searched, multiple SWAT teams were needed to execute the search warrants safely,” Tennant said.

On the day of apprehension, no victims were located, SMPD said. However, evidence was found that corroborated the serious charges that the defendants now face. Investigators assure the community that the neighborhood is safe. However, SMPD suggests that if the public sees something that seems out of place, speak up and call the police, the release said.

SMPD’s non-emergency line is (512) 753-2108. Any life-threatening crimes should be reported by calling 911, police said.