( CNN ) -- The daughter of a West Virginia sheriff gunned down in his patrol car as he ate lunch told CNN on Saturday she believes there is a strong possibility he was targeted because of his crackdown on drug dealing in the area . Mingo County Sheriff Walter E. `` Eugene '' Crum had only taken office three months before he was shot to death on Wednesday , but already had built a reputation for targeting drug dealers and so-called `` pill mills . '' `` My dad fought tirelessly against drug abuse . He just wanted to clean up the county and make it a better place to live , '' Crum 's daughter , Julie Hall , told CNN 's Fredricka Whitfield in her first television interview since her father was killed . `` Things are still under investigation at this time . We really are unsure , '' Hall said . She said her gut tells her `` it 's a strong possibility '' his killing is linked to his law enforcement activities . Investigators have not publicly identified a possible motive in the case , but they have a suspect . Tennis Melvin Maynard , 37 , is being treated at an area hospital after being shot by one of Crum 's deputies , authorities said . A witness saw the shooting and called 911 , giving police a license plate number and description of the car , the Mingo County sheriff 's office has said . According to investigators , Maynard was spotted by deputies and led them on a high-speed chase before crashing his SUV . When he got out of his damaged vehicle , he pulled a gun , they said . Authorities have questioned Maynard twice , including shortly after he was shot . They will not disclose what he said the first time , and they said he was too medicated to give a lucid statement the second time , Williamson Police Chief Dave Rockel said . A search of Mingo County court records show no criminal arrests or civil cases involving Maynard . His only citation involves failure to wear a seat belt , according to the records . Maynard 's mother , Olgie , told CNN her son spent time a state hospital for mental health issues in recent years . `` He went crazy , '' she said , explaining her son had n't been the same since he was involved in a workplace explosion five or six years ago in Alabama . `` He was out in the yard yelling . We called the police , and they took him away . '' Since then , she said Tennis had gotten more psychiatric help at another mental health center . At home in Ragland , where he lives with his parents , he mostly stayed in his bedroom and watched television . `` He talks a lot to himself , '' she said . `` ... He was never violent . '' The Bureau of Alcohol , Tobacco , Firearms and Explosives has traced the gun authorities say was used in the shooting of Crum , according to West Virginia State Police . But police have refused to release the results of the trace at this time or say whether the gun was purchased by the suspect . Crum made a name for himself within West Virginia law enforcement circles for his Operation Zero Tolerance , the anti-drug enforcement policy that he put into place shortly after taking office in January . Crum 's wife , Rosie , was appointed Thursday to finish the remainder of her husband 's term , with an election set for 2014 . `` She was the one who knew him best , and knew what he wanted to accomplish , '' Hall said . Hall said she and her brother were concerned for their mother 's safety in the wake of the shooting , but believes she is the best person to carry on their father 's legacy . `` No one can be 100 % sure of what 's going to happen , '' she said . Visitation was scheduled Saturday between 4 p.m. and 9 p.m. at Mingo Central High School , according to the family . A service for Crum is planned for 1 p.m . ET Sunday at the high school . CNN 's Susan Candiotti , Carol Cratty , Ross Levitt and Greg Botelho contributed to this report .
FIRST ON CNN : Julie Hall believes her father fought tirelessly against drug abuse . Orange County Sheriff Walter ` ` Eugene '' Crum was killed Wednesday . Hall believes there 's a ` ` strong possibility '' he was killed because of a drug problem . A service for Crum is scheduled for Sunday .