HOUSTON (AP) — Failure of a prison guard to check identification of an inmate purporting to be a worker helped lead to the escape of seven convicts, a report said.

The inmates, who remain at large, took 16 weapons and more than 200 rounds of ammunition after overpowering guards during the escape from the the maximum-security Connally Unit near San Antonio Dec. 13.

They amassed dozens more weapons in a sporting goods store robbery on Christmas Eve, during which Irving police officer Aubrey Hawkins was shot to death. A $200,000 reward has been offered for the capture of the escapees, who authorities believe are hiding in the Dallas-Fort Worth area.

According to a report by the Texas Board of Criminal Justice, which is set to be released Thursday, a guard allowed an inmate clad in street clothes who represented himself as a worker into the guard tower. The inmate overpowered the guard there and opened an exterior gate freeing the other six prisoners.

The street clothes came from a maintenance worker who had been overpowered by prisoners in an inmate lunch area, the report said.

The report cites the prison guard's failure to follow procedure as the most significant factor in the escape, board chairman Mac Stringfellow told the Houston Chronicle in Tuesday's editions.

If the guard had followed procedure, the inmates would have remained confined in the prison yard, Stringfellow said.

"If they fail to follow procedures and guidelines, then this sort of thing can happen. That's where the problem lies," he said.

On Monday, Acting Lt. Gov. Bill Ratliff urged the Senate Criminal Justice Committee to look into causes of the escape.

Stringfellow said that he doesn't object to a legislative hearing but that the report would not sugarcoat facts surrounding the escape.

"It points fingers where fingers need to be pointed," he said.

Texas' prison system has struggled in recent years with high turnover and staff shortages among guards.

"Corrections officers are left between a rock and a hard place," said Larry Blanchard, a Beaumont-based field representative for the American Federation of State, County and Municipal Employees, the union that represents guards. "It's a difficult job to do as it is, and there are not enough of them to have sufficient security measures in place."