As police and volunteer searchers scoured central Arizona on Monday for Holly Bruce, her sister issued a plea.

"Holly, you are so incredibly important,'' said Ashley Bruce, 26, of Scottsdale. "You are loved, and you are my best friend, and I need you in my life. Please come home."

Police and volunteers have been searching several days for Holly, 25, who went missing Wednesday and is believed to be suicidal.

Ashley said that the family had chartered two small aircraft to participate in the search, mostly in the Four Peaks, Payson and Fossil Creek areas of central Arizona.

Holly Marie Bruce has a troubled past, police said. She has battled depression since her father drove to a forest in Laramie County, Colo., and committed suicide 10 years ago.

Police spokesman James Holmes said recent events have contributed to a grim scenario for Holly.

Officials said a search of Bruce's home found a receipt for a handgun she purchased the same day she went missing.

Holly Bruce is 5 feet 4 inches tall and 110 pounds, and she has brown eyes and shoulder-length brown hair.

Anyone with information regarding this case is asked to call the Phoenix Police Department at 602-534-2121 or, after hours, at 602-262-6141.