Kimball was charged Monday with two counts of second-degree murder, according to the Boulder Combined Courts Clerk's office.

The charges stem from the disappearances of Kaysi McLeod, Jennifer Marcum, Terry Kimball and Leann Emry.

Count one is for Terry Kimball, Scott Kimball's uncle. Count two is for McLeod, Marcum, Emry and McLeod.

Emry, McLeod, Marcum and Kimball were all last seen with Scott Kimball in 2003 and 2004.

Kaysi McLeod's remains were recovered in a remote area of Jackson County in June 2008.

The remains of Leann Emry were found in the Book Cliffs of southeastern Utah on March 11.

Remains thought to be those of Terry Kimball were found near Vail Pass in June.

The remains of Marcum have not been found.

Investigators believe Scott Kimball, who used to work as an FBI informant, is responsible for the disappearance of each person from the Denver area.

Until now, he had not been charged with any of the disappearances.

Scott Kimball pleaded guilty to a federal gun possession charge on Jan. 22, 2008. Federal Judge Marcia Krieger ordered him to serve 70 months in a federal prison on that charge.

Kimball is currently being held in the Boulder County Jail.

To contact investigative reporter Jace Larson, e-mail jace.larson@9news.com or 303-871-1432.