The head of the Texas agency behind the seizure of more than 400 children from a polygamist group announced Friday that he is retiring.

The news release announcing Carey Cockerell's retirement as commissioner of the Department of Family and Protective Services offered no reason for his departure, but he said in the announcement that he had been thinking about stepping down since late last year.

"I'll soon be a grandfather and I'm looking forward to a lot of quality time with my family after four decades of working in state and local programs," said Cockerell, 61.

The release includes a list of Cockerell's accomplishments but makes no mention of the April raid in which all children from the Yearning For Zion Ranch in Eldorado were removed.

The Texas Supreme Court later ruled the children were improperly separated from their families.

The agency's sweeping action in the custody case raised concerns among civil liberties groups, and members of the Fundamentalist Church of Jesus Christ of Latter Day Saints said the state was persecuting them for their religious beliefs. The breakaway Mormon sect practices polygamy but denies state allegations that it has pushed underage girls into marriage and sex with older men.

Cockerell, who has served at the agency since 2005, will retire Aug. 31. Agency spokesman Patrick Crimmins said Cockerell would have no further comment.

The agency said that during Cockerell's tenure, the Legislature approved adding 2,500 case workers and support staff, workers' average case loads have dropped, residential child care inspections have nearly doubled and adoptions of children in the Child Protective Services system have increased by 27 percent.

Previously, Cockerell served for 20 years as Tarrant County's director of juvenile services.

"For many years, Commissioner Cockerell has dedicated himself to protecting those who cannot protect themselves," Gov. Rick Perry said in the news release. "I thank him for his tireless service and effective leadership."

Perry spokesman Allison Castle said Cockerell was not asked to resign.