Bonne Terre, Missouri - A man convicted of the rape and murder of a nine-year-old girl was executed on Tuesday in the state of Missouri, prison authorities said.

Christopher Collings (49) was pronounced dead at 6:10 PM at the state prison in Bonne Terre, the Missouri Department of Corrections said in a statement.

Collings was convicted of the November 2007 murder of Rowan Ford, the stepdaughter of a friend, in the rural town of Stella. Her body was dumped in a sinkhole and found several days later.

Collings' lawyers had asked the Supreme Court for a last-minute stay of execution but it was denied.

The attorneys for Collings had argued that the police chief, who obtained their client's confession and was the primary witness at his trial, had a troubled history and lacked credibility.

In addition, they said, the girl's stepfather, David Spears, confessed to involvement in her death but did not face murder charges.

Missouri Governor Mike Parson denied a clemency request from Collings, clearing the way for his execution by lethal injection.

"Mr. Collings has received every protection afforded by the Missouri and United States Constitutions, and Mr. Collings's conviction and sentence remain for his horrendous and callous crime," Parson said.

"There is not and never has been any doubt about Collings's involvement or the heinousness of his crimes."

There have been 23 executions in the US this year, including four in Missouri. The death penalty has been abolished in 23 of 50 states, while six others – Arizona, California, Ohio, Oregon, Pennsylvania, and Tennessee – have moratoriums in place.