The Casper Police Department has weighed in on the Pokemon Go phenomenon.

They want players to behave themselves downtown.

The police say that players have been littering and leaving a mess wherever they go, and one group heard the story and has decided to make amends.

Lucas Colgrove is part of a Pokemon Facebook group in Casper, and they are holding a downtown cleanup day on Sunday.

"We've gotten in touch with the Keep Casper Beautiful folks and they've given us trash bags and a receptacle to put everything in when we're done," Colgrove says.

Colgrove says he thinks most players are not causing problems for local businesses.

"I think most players are responsible people, but there are always some who can ruin a good thing for everybody," he told us.

But the group want to make sure no one blames the game or the players for any problems.

In fact, he feels businesses can benefit from the game.

It gets people off the couch and out to places they might not ordinarily go and many of those businesses can take advantage of that," Colgrove added.

The cleanup day begins at Sunday at noon at the America Theater.