I don't want to get pedantic (though I can't help it often), but define 'Love'.
If you mean as the Greeks defined it a Phileo love (brotherly, familial, fellowship) then yes, I think it's OK to love someone who's committed a terrible crime less...particularly if there is no tie between you...than you would a neighbor, a friend, or a family member. We're not called on the be 'friends' with people who do evil.
If such a person WERE in your circle of Phileo loved ones, then a greater love Agape--sacrificial, without expectation of return--would have to take over and you'd be called on to love them MORE than you would love a more casual friend or family member.
If such a person were NOT in your circle of loved ones--a stranger (more or less)--then at the very least we'd be called on to not hate them, and we might be led of the Spirit to love and minister to them with a greater love than we might show to those we naturally care for.
The problem with these times in our media age is that we think we know LOTS of people who we really don't and are exposed to faces, celebrities, criminals constantly. Unless we are called on to specifically actively love and minister to these people, then again, we're only called on to not hate them and to pray for them as we are led.
"Active" is the key word. Love is doing, not just feeling. We encounter strangers with kindness and humility and an attitude of love. If God leads us across the paths of 'people who have committed gross sins against God and Humanity' then we are to love them too. All of us are guilty of gross sins against God and Humanity, after all.