ID=72285538BOISE -- The man accused of shooting a Boise woman could face more charges in his next court hearing. Christopher Wirfs is being held in the Ada County Jail on a $1 million bond. He is charged with aggravated battery and weapons charges in relation to the shooting of Makaela Zabel-Gravatt.

In a phone call with KTVB Wednesday, prosecutor Dan Dinger said there is the possibility of more charges, but did not elaborate. He said he could not speak directly to this case, but he explained aggravated battery and attempted murder both carry a 15-year maximum sentence. Dinger said attempted murder is much more difficult to prove than aggravated battery.

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In Monday's arraignment, the prosecutor said Wirfs had been contacting Gravatt and showing up at her work place, including on the day she was shot. He said Wirfs had essentially been stalking Gravatt, including leaving voicemails saying he would kill her.

Stalking Resource Center Consultant Jennifer Landhuis says threatening voicemails can be part of stalking behavior.

"The stalker is sending unwanted letters, unwanted gifts, showing up in places they aren't supposed to be," said Landhuis. "What we are seeing in the last decade is the use of technology to stalk."

Stalking is defined as a course of conduct, meaning multiple incidents, where there is unwanted contact between the stalker and the victim that would cause a reasonable person to be fearful.

"Stalking is a unique crime in that we are relying on the individual who experienced the stalking to pretty much build their own case," said Landhuis.

Boise Police Detective Chad Wigington and Landhuis stressed the most important thing for a stalking victim to do is keep a log of what has happened, especially because reports may go across different jurisdictions.

Officials said Gravatt had contacted police before.

"In this case in particular there were documented reports," said Wigington. "Those were in the process of being reviewed."

Police or victim protection groups may provide someone with a stalking kit. It comes with items like a diary log, an audio recorder, and a cell phone.

"We don't want people who are experiencing stalking to change their phone number," said Landhuis. "That sounds contrary to popular belief... It's not like the stalker is like 'Oh darn they're not answering their phone I guess I'll give up on stalking them.' Instead they go follow them in person."

Wigington also says it's important to be clear about no contact. If a victim still talks to their stalker occasionally, it can become a gray area.

If someone is stalking a victim, it can be difficult to make them legally stay away.

"What we also have a difficulty with in the State of Idaho is there is no civil protection order for stalking victims if they are not related to the person who is stalking them," said Landhuis.

"I do know there was a protection order filed at one time that was declined, so that is also frustration," said Wigington, but he did not know why the court system denied it.

"In this individuals case, I certainly can't speak to any of the details, but I think the escalating behavior would have occurred no matter what happened," said Wigington.

Wigington said victim's work place had a no trespassing order against Wirfs. He said on the day of the shooting there was a trespassing citation signed against Wirfs, but officers weren't able to reach him to serve the citation.

If you are a victim of stalking, resources are available here.