DENVER -- A man who was the focus of a CALL7 investigation on the Denver Department of Human Services was sentenced Friday to 36 years in prison for killing his infant daughter.

Luz Valdez died Dec. 30 and Isidoro Valdez-Ruelas admitted to shaking her.

Denver Department of Human Services workers had visited the family home days before her death but did not interview Valdez-Ruelas and left Luz in the home.

Luz was one of four children who died after DDHS workers failed to recognize they were in danger and remove the children from their homes, the CALL7 investigation found. The investigation led to several internal reviews with recommended changes and after months of damaging stories the DDHS director resigned to take a job at a non-profit.

Luz's mother, Mary, told the court that she wonders what she did to deserve the death of her baby and she asked for a maximum sentence for Valdez-Ruelas.

“I won’t feel right until he gets the maximum time in jail,” she said told Denver District Judge Shelley Gilman.

Valdez-Ruelas apologized to Mary, her family and the court, saying he was stressed and didn’t intend to hurt Luz.

“I just was not using all of my five senses,” he said through an interpreter. “I didn’t think this was going to happen to my daughter.”

The plea bargain specified a range of 16 to 48 years and Gilman chose the higher end of the range because Valdez-Ruelas did not seek immediate medical help after shaking Luz.

“Nothing can be done to bring back a beautiful young girl,” Gilman said.

After the hearing, the family members said Valdez-Ruelas should have received a longer sentence.

Luz would have turned 1 on Sept. 4.