. >> reporter: joe bernal is now leasing some land from water asset management. he says ranchers here are keeping an eye on their new neighbors. >> and we'll be watching for what may be coming. >> reporter: ben tracy, cbs news, grand junction, colorado. >>> police say a man armed with an ar-15 rifle opened fire today inside a target store. how it all ended, next. one prilosec otc each morning blocks heartburn all day and all night. prilosec otc reduces excess acid for 24 hours, blocking heartburn before it starts. one pill a day. 24 hours. zero heartburn. when you really need to sleep. you reach for then really good stuff. zzzquil ultra helps you sleep better and longer when you need it most. its non-habit forming and powered by the makers of nyquil. >>> there were some terrifying moments today for shoppers and workers at a target store in omaha, nebraska, when a man allegedly armed with an ar-15 rifle opened fire. police responded quickly to the scene and shot him dead. no one else was injured. investigators say the gunman was carrying a lot of ammunition. >>> s

>> reporter: colorado rancher joe bernal has just one source of water-- the colorado river.at river is your lifeline. >> that's it, that's all we've got, is that river. >> reporter: and that river is why someone new bought this land just down the road. >> water asset management owns that property. >> reporter: and when you first heard of them, what was your reaction? >> surprise and concern. they are concerning, because they're large. >> reporter: water asset management is a new york investment firm with offices inside this building. in the past five years, it has bought at least $20 million worth of land in western colorado. >> these are folks that have identified the drought as an opportunity to make money. >> reporter: andy mueller's job is to protect colorado's share of the river. he says water asset management has acquired 25 million acres of land for the water rights that come with it. >> with the intent not to use the water, and send the water downstream to an entity or entities that might pay them quite a bit of money. i view these private drought- profiteers as vult