A series of violent threats against South Bay schools this past week prompted heightened police presence, some arrests and an ongoing conversation about how to respond to these kinds of scares. San Jose State University and a few K-12 districts in San Jose and Milpitas reported incidents that stoked fresh fear in the wake of the school shooting last month that left 17 dead in Parkland, Florida.

One incident took place the afternoon of Feb. 28 at SJSU, where someone spotted bathroom graffiti that read: “Shooting 2.28. 2day 5pm.” A witness alerted the University Police Department to the message, which was scrawled on the wall inside of the women's bathroom on the third floor of Dudley Moorhead Hall.

The rest of the SJSU community was alerted through email and text from the campus-wide emergency notification system AlertSJSU. But some students first found out by word of mouth after information and photos began circulating on social media.

UPD Capt. Alan Cavallo said the situation was not taken lightly, and that he had officers on high alert, patrolling on foot and by vehicle. The San Jose Police Department was also notified of the threatening message and was keeping an eye on the situation.

Another scare took place that same day when after someone posted on Twitter about wanting to “shoot up” Alum Rock schools. SJPD’s Human Trafficking, Juvenile, Missing Persons Unit tracked down and identified the author as a 12-year-old girl, who, according to the initial SJPD press release, was questioned but not taken into custody. However, a second media bulletin indicated that she was later arrested, however.

Elsewhere in San Jose, in the Oak Grove district, parents got an email from administrators that their campuses were “targeted for possible violent acts” in a social media posting. Confusion and frustration spread as parents criticized the district for failing to give them enough information and then allegedly downplaying the incident. Some parents say the got no notice at all.

But the scare in Oak Grove turned out to be unfounded. SJPD later confirmed that there were no threats reported against that school district. Superintendent Jose Manzo said the email he sent out was actually a response to the Alum Rock incident, and that the wording of the message was misleading.

Another violent message was reported in Milpitas, which led police to keep close watch on local schools. But they were unable to determine whether it was a valid threat.

According to news reports, similar threats took place throughout the U.S. in recent days. Experts say it's a common trend in the wake of a high-profile school shooting.

“Yes, kids can see these events on the news and relate to the shooter, be inspired and emulate them,” University of San Francisco criminology and sociology professor Kimberly Richman told KRON 4 in a March 1 newscast.