the character of Lawrence was partly based on a gay friend of the author's, Michael Boncoeur, who was murdered by a bicycle thief. The attitude of the police at the time was to make the murderer into the victim solely because Boncoeur was gay, which may be why the strip differs from other family strips in its unwillingness to uncritically praise the police.
I thought that Lawrence was based on Lynn's brother-in-law? And I can't recall any strips where the police weren't portrayed in a good light, unless you count Paul's "betrayal."