The victim was taken to a Portland hospital for treatment to numerous injuries. Police said they are not considered life-threatening.
Neighbors reacted to the allegations Monday night.
"It's sickening that someone could have such anger in them, strangling with their own hair? I mean strangulation period, you have a lot of anger, but it's shocking that someone like that would be on our street," said neighbor Ric Leonetti.
"The scariest part of it, is that she was probably screaming and trying to get help, but no one else was around to help. It's unnerving being a woman, and knowing that could happen across the street and no one can notice," said neighbor Molly Dickinson.
Grotberg is set to be arraigned in court Tuesday.
Police said domestic violence crimes in progress should be reported to 911. There are 24-hour resources available for victims of domestic violence on the Portland Women's Crisis Center Line at (503) 235-5333 or 1-888-235-5333.
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