PHOENIX - Arizona Department of Corrections Director Charles Ryan is concerned about the number of arrests involving employees in recent years.

During the past 4 1/2 years, Ryan said, there have been 640 staff arrests - ranging from suspicion of domestic violence, fighting, assaults, drug use and drunken driving.

In his "Director's Desk" blog on the DOC website, Ryan said employees "should be keenly aware of the need" to conduct both their personal and professional lives "in a manner that is above reproach."

Corrections spokesman Bill Lamoreaux told The Arizona Republic that Ryan wrote about the problem to encourage other employees needing help to use a confidential, free employee-assistance program.

Lamoreaux said the number arrested averages out to about 142 employees - or 1.5 percent of the 9,278 DOC staff members - on an annual basis.

Records released by DOC show there were 140 citations or arrests of staff in fiscal 2012. That was a slight drop from 147 the previous year.

Since fiscal 2009, the biggest problem has been driving under the influence, which accounted for 232 of citations and arrests during the period.

The second-largest issue was domestic violence, with 134 arrests. Drug crimes accounted for just 21 arrests during the same time period.