Is my husband wrong for not trying to help his colleague

My husband is a police officer and we have both been on FMLA leave for about a month. He found out one of his colleagues is facing criminal charges for SAing his 13 year old step daughter. My husband was asked to write him a character reference letter for court. Some of his other coworkers already have. My husband declined. They were saying he didn't do it and that the step daughter has a lying issue and is also super promiscuous. My husband said that's for the court and jury to decide. If he's innocent he hopes it gets cleared up but he isn't attaching his name to anything involving alleged child abuse. He just wants to enjoy our new baby. My bil thinks my husband is wrong because he knows the guy and knows whether or not he would do that. My brother is also a police officer and said you have to look out for your fellow officer. My husband has made up his mind. He said he doesn't THINK this person would do that but he doesn't know and he wasn't there and he's not going to write any character letters. If he didn't do it his name will hopefully be cleared. If he did then he would have just defended a predator so he's not getting involved. I agree with him. My brother doesn't and some of my husband's coworkers don't. My dad said maybe if it was family and they truly believed they didn't do it he would but he would not do that for a colleague. Was my husband wrong or right?