Kent Sprouse acknowledged almost immediately after he was arrested more than a decade ago that he killed a police officer and another man outside a Dallas-area convenience store . A jury decided in 2004 that he should be put to death , and unsuccessful appeals since then have focused on whether Sprouse was mentally ill at the time of the slayings in 2002 and should be spared the death penalty . No new appeals are pending as Sprouse 's lethal injection scheduled for Thursday evening approaches . He would be the fifth inmate executed this year in Texas , the nation 's most active death penalty state . Death row : Kent Sprouse gunned down Ferris Police Officer Marty Steinfeldt , 28 , at a gas station outside of Dallas before also shooting dead a customer , Pedro Moreno , 38 , in 2002 . Sprouse was convicted of the death of Ferris Police Officer Harry Marvin 'Marty ' Steinfeldt III , who was shot outside the Ferris Food Mart about 20 miles south of Dallas . Steinfeldt , 28 , was responding to a 911 call about a customer shot outside the store . Witnesses said Sprouse carried a shotgun into the store the afternoon of Oct. 6 , 2002 , while he made a purchase and then walked outside and fired toward two men at a pay phone . He went to his car and appeared to have some trouble with it , then shot and killed a customer , Pedro Moreno , 38 , who was pumping gas nearby . As Steinfeldt drove up , he was met with gunfire and hit twice under the arm where his vest did not protect him . He managed to fire 17 shots and wound Sprouse in the chest , leg and hand . Court records indicate that Sprouse told an officer who accompanied him to a hospital that he believed Moreno was an undercover officer , so he shot him . 'And I shot the other officer that was in uniform , ' Sprouse said , according to the records . Medical tests showed Sprouse , a Boone County , Missouri , native , had taken illegal drugs within the previous 48 hours . 'He started hitting the meth and went crazy , ' Jim Jenkins , his lead trial lawyer in 2004 , recalled last week . 'Even his family was afraid of him . ' Kent Sprouse , 42 , was sent to death row for a 2002 shootout at a Ferris , Texas , convenience store that killed police Officer Harry Steinfeldt III ( right ) andcustomer Pedro Moreno , whom Sprouse had asked for help repairing his car . Jurors rejected an insanity defense and pleas for a life prison term . Sprouse was charged but not tried for Moreno 's death . 'It was a senseless taking of two human lives , ' Don Maxfield , the now retired Ellis County chief felony prosecutor who handled Sprouse 's trial , said last week . 'It 's just a sad story all the way around . ' The U.S. Supreme Court in November refused to review Sprouse 's case . Ferris Police Chief Sam Love said he and several of his officers plan to be outside the Huntsville Unit prison Thursday evening to show support for their deceased colleague . Steinfeldt had been with the Ferris department about two years after serving as a police officer in the Army . ' I do n't think it 's too soon or too long or whatever , ' Love said of Sprouse 's scheduled lethal injection . 'My feeling is the criminal justice system has done its work and we can move on now . ' Scene : Sprouse is expected to be executed about 6 pm Thursday in Huntsville , more than 150 miles southeast of Dallas , by lethal injection . The process is expected to take 15 to 30 minutes at most . Texas Department of Criminal Justice officials said a recent purchase of pentobarbital means they have enough of the sedative to carry out Sprouse 's execution and three others set for this month . The state 's supply will need to be replenished for at least three other executions that are scheduled in May and June . Death penalty states have found it increasingly difficult to acquire drugs as manufacturers , bowing to pressure from death penalty opponents , refuse to sell to state prison agencies for use in capital punishment .
Kent Sprouse , 42 , faces lethal injection at evening . In 2002 he gunned down Ferris Police Officer Marty Steinfeldt , 28 , at a gas station outside of Dallas and a customer , Pedro Moreno , 38 . Sprouse was high on meth , but his insanity defense was rejected . He was sentenced to death in 2004 . Sprouse has not appealed the sentence recently . It could be the last execution in Texas for a while . The state has a shortage the lethal drug pentobarbital .