SAN DIEGO -- A man was detained Thursday for allegedly stabbing an Otay Mesa barber who had given him a haircut he considered unacceptable, authorities reported.

Joshua Robert Schwartz, 20, allegedly attacked the 60-year-old shop owner shortly after 6 p.m. Wednesday as the victim was closing his Coronado Avenue business for the night, according to the San Diego Police Department.

After slashing the barber twice in the face, the assailant ran off, SDPD Sgt. Rich Nemetz said.

"The motive for the attack appears to be that the suspect was unhappy with a previous haircut," Nemetz said.

A witness followed Schwartz to the 900 block of Outer Road, where patrol officers took him into custody.

Medics took the victim to a hospital for treatment of apparently non-life-threatening wounds.

Schwartz, who was booked on suspicion of assault with a deadly weapon and held on $30,000 bail, is expected to be arraigned Friday afternoon.