A California teen accused of brutally stabbing a 73-year-old grandmother allegedly had a chilling urge to kill before the deadly mall attack.

Tyler Leibelt, 19, pleaded not guilty Wednesday to charges stemming from the July stabbing death of Rachell Summers — a brand new grandmother — outside the Capitola Mall in Northern California.

Leibelt is charged with felony first-degree murder and use of a deadly weapon in connection with the killing.

The Santa Cruz resident was a student at Cabrillo College when the alleged attack unfolded. Investigators say Leibelt traveled to the college by Uber before suddenly feeling an urge to kill someone.

He allegedly shut off his cellphone and boarded a METRO bus bound for Capitola Mall, where he went into Big 5 Sporting Goods and bought two switchblade knives.

The teen allegedly considered attacking an elderly Asian man before turning his attention to Summers, who was caught off guard.

He allegedly stabbed the 73-year-old more than 11 times, according to the Santa Cruz Sentinel.

Leibelt also allegedly thought about killing multiple people and robbing a Macy’s at the mall before ultimately attacking Summers.

Authorities had previously expressed concerns about Leibelt’s alleged violent intentions.

The Santa Cruz County Sheriff’s Department sought a gun violence emergency protective order against the teen in November after expressing a “desire to cause a mass casualty event.”

Court records also state Leibelt previously disclosed homicidal “fantasies” and complained that he “kept getting let out” of custody, a remark expected to intensify criticism over his release while facing another felony case.

Prosecutors say Leibelt was awaiting trial in another felony case and living in a sober living environment when Rachell Summers was killed on July 20.

Summers was a gallery manager at Art of Santa Cruz and had become a grandmother for the first time just last year.

“Her passing has left a deep void in the lives of everyone who loved her, especially her grandson. Rachell became a grandmother for the very first time last year, and her only grandchild will soon be celebrating his first birthday,” a GoFundMe set up for Summers stated.

Leibelt remains in custody at Santa Cruz County Jail without bail.

He is scheduled to return to court Oct. 10 for the setting of his preliminary hearing.