-LRB- CNN -RRB- -- Jurors started to deliberate Friday after prosecutors and defense attorneys made closing arguments in the murder trial of an anti-abortion activist charged with killing a doctor who performed late-term abortion procedures . Scott Roeder is charged with murder in the death of Dr. George Tiller , who was shot to death May 31 in his church in Wichita , Kansas . Prosecutor Ann Swegle urged jurors to convict Roeder , reminding the jury of the defendant 's testimony Thursday . `` His testimony was delivered very matter-of-factly , but its contents were chillingly horrific , '' she said . `` He carried out a planned assassination , and there can be no other verdict in this case ... other than guilty . '' Kim T. Park , chief deputy district attorney , told the jurors that Roeder 's actions were unjustified and cowardly . `` Scott Roeder is not justified , '' she said . `` He is only and simply guilty of the crimes he is charged with . '' Mark Rudy , a defense attorney for Roeder , told jurors that Roeder believed he had to act . `` Scott thought that the babies kept on dying , '' he said . `` Scott formed a belief that he had to stop George Tiller from killing more babies . '' He admitted that Roeder killed Tiller but said only the jurors can decide if Roeder `` murdered '' Tiller . He said he was not asking jurors `` to check your common sense at the door '' and urged them to `` represent our little part of the nation well . '' `` No defendant should ever be convicted based on his convictions , '' Rudy said . Roeder testified Thursday that he shot and killed Tiller and did not regret it . `` There was nothing being done , and the legal process had been exhausted , and these babies were dying every day , '' Roeder said . `` I felt that if someone did not do something , he was going to continue . '' Tiller ran a women 's clinic at which he performed abortions . Sedgwick County District Judge Warren Wilbert ruled after the end of testimony Thursday that the jury could not consider a lesser charge of voluntary manslaughter against Roeder as the defense wanted . In making the ruling , Wilbert noted that Roeder had been talking about killing Tiller for 10 years , CNN affiliate WDAF reported . Several of Tiller 's family members broke into tears as Roeder recounted the shooting . Roeder said he did n't regret what he did and felt `` a sense of relief '' when he learned that Tiller 's clinic was shut down after his death . Roeder calmly testified that he thought about different ways to kill the doctor -- driving a car into his , perhaps , or shooting him with a rifle . He also considered cutting Tiller 's hands off with a sword , but decided that would not be effective , as Tiller would still be able to train others . Tiller , 67 , was one of the few U.S. doctors who performed late-term abortion procedures . He had already survived one attempt on his life before he was killed . He decided to kill Tiller at his church , he said , because `` I felt that actually if he was to be stopped , that was probably the only place he could have been stopped . ... It was the only window of opportunity I saw . '' Roeder said he visited the church four or five times before Tiller 's death . The week before the shooting , on May 24 , he carried a .22 - caliber handgun with him , he testified , but Tiller did not attend church that day . On May 31 , though , the doctor was there , and `` I did what I thought was needed to be done to protect the children , '' Roeder said . `` I shot him . '' `` The lives of those children were in imminent danger if someone did not stop George Tiller , '' he said . The defense had sought to have former Kansas Attorney General Phill Kline and current Deputy Attorney General Barry Disney testify , but the judge did not allow it . Kline unsuccessfully attempted to prosecute Tiller in 2006 , and Disney charged Tiller with 19 misdemeanor counts , but a jury acquitted him . Wilbert said Roeder could testify about the cases and how they affected his beliefs , but to allow testimony from Kline would `` get into legal matters that do not concern this jury . '' And , the judge said , the cases do not give Roeder a basis to state absolutely that Tiller 's actions were illegal , since the doctor had never been convicted . Defense attorneys claim Roeder was led to shoot Tiller in part because of authorities ' failure to punish him through the judicial system . Roeder testified he was `` very frustrated '' by Tiller 's acquittal , saying it `` seemed like that was the last attempt by the state of Kansas to find if there was anything at all going on illegally in George Tiller 's clinic . '' Roeder could face life in prison if convicted of first-degree murder . He also is charged with two counts of aggravated assault for allegedly pointing his gun at two other ushers as he fled the church .