HOUSTON -

Authorities have raised the reward for one of Texas' most wanted sex offenders.

The reward has been increased to $13,000 for anyone with information leading to the capture of John Arthur Volker.

He is wanted for probation violation.

According to the Texas Department of Public Safety, in order to receive the increased reward the tip must come in during the month of August.

Authorities say all tips are guaranteed to be anonymous.

According to a statement released by DPS, Volker has ties to several cities in the Houston area, including Splendora, Spring, Conroe and Humble, as well as Houston.

He has also previously lived in southern California, near Los Angeles and San Diego.

His criminal history includes indecency with a child-sexual contact, involving two young girls.

DPS warns not to attempt to apprehend this fugitive; he is considered armed and dangerous.

There are four different ways to provide anonymous tips: Call the Crime Stoppers hotline at 1-800-252-TIPS (8477); text the letters DPS – followed by your tip – to 274637 (CRIMES) from your cell phone; submit a web tip through the DPS website by selecting the fugitive you have information about, and then clicking on the link under the picture, or submit a Facebook tip at http://www.facebook.com/texas10mostwanted by clicking the "SUBMIT A TIP" link (under the "About" section).