They told police that they had shouted at him to stop but he carried on, ignoring their protests.
Eight pit bulls were found in the 58-year-old's house, along with a firearm and ammunition.
Marsonek was arrested on two counts of firearm possession by felon, animal cruelty and sexual activity involving animals.
This isn't the only recent case of people having sex with animals.
Last week we reported on Reid Fontaine, who was allegedly caught having sex with a cow while his pal filmed it.
And a Nigerian man admitted to having sex with a goat multiple times, claiming to have asked the animal's permission first.