BY LOREN LISTIAK SUN STAFF WRITER A 19-year-old man charged with killing a Yuma youth with a baseball bat has pleaded not guilty to felony charges of second-degree murder and aggravated assault with a deadly weapons. Ricardo Julian Ortiz, 19, of 1857 S. 17th Ave., entered the plea Friday during his arraign ment before Judge pro tem Den ise Gaumont. After entering the pleas, Mike Donovan, Ortiz’s attorney, requested a hearing to review the amount of bond on which the defendant is being held in Yuma County jail. Currently, Ortiz is being held in lieu of a $1.5 million bond set by Yuma Justice of the Peace Rich Donato Sept. 24, the same day the victim, Jesus Eduardo Valenzuela, 17, died in a Phoenix hospital. When he was arrested on Sept. 20, Ortiz was jailed on a $144,000 bond. Valenzuela had suffered a serious head wound when he was attacked Sept. 15 in the 3200 block of Columbia Avenue. Yuma County sheriff's depu ties reported Ortiz was identi fied as the man who hit Valenzu ela in back of the head with a SEE KILLING/B2