The man suspected in murdering a Houston police sergeant is an undocumented alien, the U.S. Immigration and Customs Enforcement said on Wednesday.

Elmer Manzano was finally taken into custody after the police responded to a call for a domestic dispute, but not before Sgt. Harold Preston, 65, who was a weeks away from retirement, was fired. Preston was killed because of his injuries.

“Elmer Rolando Manzano-Martinez, 51, is a citizen of El Salvador and convicted criminal alien who is unlawfully present in the U.S. On Oct. 20, officers from U.S. Immigration and Customs Enforcement’s (ICE) Enforcement and Removal Operations (ERO) in Houston, Texas, placed an immigration detainer with the Harris County (Texas) Sheriff’s Office (HCSO) on Manzano-Martinez after he was arrested for murder,” ICE said in a statement to The Texan.

Manzano’s arrest record contains charges of abuse and domestic violence from 1994 to 2002.

Ken Cuccinelli, acting Deputy Secretary of the Department of Homeland Security, related the past to the tragedy of this week.

“The killing of this police officer and violence in this household were entirely preventable crimes that could have been avoided had this person been deported at times of previous convictions,” Cuccinelli told The Washington Post. “This is an unrecoverable tragedy for the officer’s family that can never be fixed.”

The news stirred up emotions on Twitter.

Police were called to Elmer Manzano ‘s residence twice in the last few days before the 41-year-old Preston was shot dead, but no charges were filed.

In the incident in which Preston was killed, Elmer Manzano and his 14-year-old son were wounded in an exchange of gunshots, authorities said. Courtney Waller, Houston officer, was also injured.

Houston Police Chief Art Acevedo said the officers had talked to Manzano’s exiled wife, who told the officers she wanted to take her belongings from the apartment they had shared with her. The police then went to talk to Manzano.

The 14-year-old unlocked the door of the apartment and reportedly told police his father had a firearm. Manzano then allegedly fired.

According to KIII-TV, Elmer Manzano was first arrested in 1994 for the alleged unlawful carrying of a firearm. The charge was dismissed after deferred adjudication, the outlet reported, citing Dallas County court records.

In 2000, Manzano was twice arrested for alleged assault and sentenced to six months in jail each time.

These incidents were followed by a May 2001 arrest for alleged felony assault. After two years of deferred adjudication, the case was dismissed.

Elmer Manzano was sentenced to 120 days in jail after pleading guilty in December 2002 to evading arrest with a motor vehicle. A protective order was issues against him was issued in 2004.

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