(CNN) This "good Samaritan killing" outraged people in Baltimore and beyond.

Jacquelyn Smith's husband called 911 on December 1, according to police, saying she had stopped her car to hand money to a needy woman with a baby when a man approached. He said the man reached for her wallet, fatally stabbed her in a struggle, and fled with the woman and baby.

Keith Smith

Valeria Smith

But the investigation took a twist Sunday when her husband, Keith Smith, 52, and his daughter, Valeria Smith, 28, were taken into custody by Texas authorities in Harlingen, near the Mexican border, acting Baltimore Police Commissioner Michael Harrison said at a news conference.

Warrants charging Keith and Valeria Smith with first-degree murder have been issued, he said. Warrants released Monday by the Cameron County Sheriff's Office in Texas said both were also charged with conspiracy to commit murder, assault, conspiracy to commit assault and a weapons charge.

"During the course of our investigation, we developed evidence that Mr. Smith was leaving Maryland, so we made the appropriate national notifications and the Texas State Police arrested him this morning," Harrison said.

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