SAN DIEGO -- A man accused of robbing small businesses across San Diego County over a one-month period, and threatening to shoot female employees if they didn't hand over cash, pleaded not guilty Wednesday to 20 robbery counts.

Dragon Jones, 41, was ordered held on $750,000 bail.

Deputy District Attorney Amy Maund told reporters outside the courtroom that law enforcement gave Jones the nickname the "Back Room Bandit" because after each robbery, he would allegedly order a lone female employee to the back of the store and order her not to call police.

Jones allegedly told his victims that if they called police, "he'd be back," the prosecutor said.

Maund said that from Sept. 25 through Oct. 29, Jones allegedly robbed 20 yogurt shops, ice cream shops, lingerie shops, hair and beauty supply stores and Hallmark shops in Poway, La Mesa, San Diego, El Cajon, Chula Vista, National City and Lemon Grove.

The prosecutor alleged the defendant would enter a business that usually had one female working and ordered her to open the cash register, displaying what was believed to be a real gun.

If the victim hesitated to hand over the money, Jones would threaten to shoot her, Maund alleged.

In each of the robberies, Jones allegedly got away with under $100 to $200. A fingerprint left at a crime scene led authorities to Jones, Maund said.

She said the defendant was arrested Oct. 31 as he tried to come back into the United States from Mexico at the San Ysidro Port of Entry.

Jones faces 24 years in state prison if convicted. A status conference was set for Nov. 12 and a preliminary hearing for Nov. 19.