Nagel is also accused of contacting Ms Erbe's 14-year-old daughter professing his love for her and growing increasingly angry over being unfriended by them on Facebook.
Jurors heard that Nagel wrote bizarre things about his target including, 'I want her to open her eyes to look in mine and make love'.
A Christian by religion, her family has got mixed Euro and Indo American ethnicity.
Kathryn is everything and everything is Kathryn'.'I get mad if I read about another guy loving her. Prosecutors say that Nagel is a big Batman enthusiast and even named one of his daughters Batgirl and the other Harleyquinn.
Nagel allegedly tried to get close to the actress by forcibly trying to hug her in a Manhattan location where the TV show was filming a scene.
His family were with him at the time and a security guard ordered him to leave the set.
The brother of TV star Kathryn Erbe said that he unwittingly became Facebook friends with a man accused of stalking his sister.
Jonathan Erbe who accepted the friend request from Charles Nagel said: 'I thought he was someone I knew or was associated with my business'.