Murder is considered one of the worst offenses in any society. But this person was already punished by society, and seen fit by the law to return to it. So what could explain your continue (and very understandable) discomfort? Is it because you believe that the penal system did not properly make this person safe to return to society? Is it because that once someone has committed such a terrible crime that they are inevitably going to be able to do so again, because they have the psychological profile to do it? Such a person is more likely to slip into violence? Finally, does it mean that such a person is forever marked as fundamentally dangerous and unworthy of reintegration?
After the visceral recoil that is an instinct that preserves safety, you have to examine why you are so opposed to working with someone who has committed such a crime. Because we claim to live in a free society that gives people the liberty to pull themselves up from the bootstraps no matter their circumstances, yet discriminates against those who have done the time. Because we claim this society is built upon Christian and post-Christian Enlightenment principles, yet we reject the power of redemption and modern methods of recovery. It's fine to have such an opinion, but you have to justify it, because it's an example of how our society operates.