For those curious, There are at least 2 real life serial killers I can think of off the top of my head who were known to have dressed in women's clothes.
In the late 60's,
Jerry Brudos killed at least 4 women, and attempted to abduct several others. Specifically, he dressed in women's clothes when he abducted 18 year old Karen Sprinker in May 1968, who he then raped, strangled, and then fucked her dead body several times before cutting off her breasts to make plastic molds with. Brudos was known to have a fascination with women's clothes, particularly underwear and especially shoes. He had tons of women's shoe catalogs with him in prison which he used as wanking material instead of porno mags.
More recently,
Col. Russell Williams started his criminal history off by breaking into at least 82 homes to steal woman's and little girl's underwear before he escalated to sexual assault, rape, and two different murders.
He also took pictures of himself modelling the underwear he stole: