San Diego police were investigating two separate shooting sprees, in May and September, that they did not believe were connected

San Diego police have arrested a 19-year-old man in connection with pellet gun attacks in the Hillcrest neighborhood, a hub for members of San Diego's LGBTQ+ community, which prompted a hate-crime investigation.

Hernan Garduno Hernandez, 19, was expected to be arraigned Friday on 21 charges in connection with a series of drive-by shootings.

San Diego police were investigating two separate shooting sprees, in May and September, that they did not believe were connected. It is not yet clear which of the sprees investigators have linked to Hernandez.

The May attacks started in the early morning hours of the 18th at several businesses that make up the gay scene in Hillcrest, including:

Surveillance video from The Rail showed the moment the bar's security guard was shot in the arm by a pellet. Police said at least 3 people had varying degrees of injuries, none that were life-threatening.

Authorities believe the pellets were fired from what's often called an "Orbeez" gun that shoots gel pellets.

The same night, a man was targeted by the gel pellets while walking with his wife in Old Town -- an assault that is not believed to have been hate-motivated, police said.

In those five attacks, the suspect vehicle was described as a black late-model sedan with one or more occupants. A $2,000 reward was offered this week for tips that led to an arrest in this case. It was not clear if that reward led to the arrest of Hernandez.

Those incidents are separate from the series of pellet gun attacks in Hillcrest that happened in early September, which are being investigated by San Diego police as possible hate crimes. The suspects in the September incidents were seen driving a light-colored minivan, and there were at least four victims that were not seriously injured, SDPD said.

SDPD Lt. Jason Weeden said the most-recent attacks are not believed to be connected to the May incidents.