PITTSBURGH — A university researcher who has been a vocal critic of gas drilling says he is leaving his post because the university doesn't want him speaking publicly about environmental issues.

Conrad “Dan” Volz is director of the Center for Healthy Environments and Communities at the University of Pittsburgh Graduate School of Public Health.

He told a Pittsburgh newspaper that he was not fired and has not been under pressure to resign. But he said there is a “basic philosophical difference” between his calling for public health advocacy and the university's preference for scholarly research.

Volz said drinking water is being contaminated by drilling on the Marcellus shale and is among the critics of “fracking” in which water, sand and chemicals are shot into the shale to free the gas.

PITTSBURGH — Pittsburgh police say they had to use a stun gun on an unruly fan during a weekend Pirates game.Authorities say 41-year-old Scott James Ashley, of Friendship, was being escorted from his seat during Saturday night's game against Colorado when he threatened another man.According to a criminal complaint, a police detective then told Ashley he was under arrest. Ashley allegedly refused to put his hands behind his back and one officer used his stun gun to no effect before police subdued him using their batons.A police spokeswoman said the chief will review a video of the arrest that was posted on YouTube.Ashley was being held on $5,000 bail on charges including disorderly conduct and resisting arrest.

SOMERSET — A man accused of beating his wife to death and setting fire to her car almost three decades ago has been convicted of first-degree murder. Jurors in Somerset County deliberated for about six hours before convicting 61-year-old John Dawson on Friday night in the November 1981 death of Kathleen Dawson.Dawson, who was arrested in April 2009 in Florida, took the stand on Thursday and denied that he killed his wife. He testified that he loved his wife despite the fact that he had cheated on her. Defense attorney Joseph Policicchio called the prosecution's case “speculation.”