A high school student was arrested and charged in connection with one of the threats.
Two Monmouth County high schools were placed on lockdown in the past two days for threats that are not related, officials said.
On Monday at around 12:30 p.m., Neptune police were called to the township's high school for a threat within the school, Capt. Michael McGhee, the department's public information officer, said.
The threat regarded a potential safety concern within the building and came in the form of an anonymous 911 call, McGhee said. School officials placed the building on lockdown until it was cleared by police officers.
Three other schools in Neptune were also placed on lockdown as a precaution, McGhee said. The lockdown was lifted after approximately 20 minutes.
Investigators with the Neptune Police Department and Monmouth County Sheriff's Office Communications Center identified a Neptune High School student as a suspect, and he was arrested Tuesday.
The student, who was later released to his parents, was charged with creating a false public alarm.
Meanwhile, about 6 miles south in Wall Township, police responded to the high school around 11:19 a.m. on Tuesday for a report of a possible threat.
The school was placed on lockdown as officers investigated the reported threat, which was unfounded, Detective Lt. Greg Carpino, the Wall police spokesman, said.
Though the school was deemed safe, officers remained on the campus for the remainder of the day. It's unclear what the threat regarded, and Carpino did not immediately return an email Tuesday evening seeking further information on the incident.
McGhee said the two incidents couldn't be related because the Neptune suspect was in police custody when the Wall threat was reported.
Alex Napoliello may be reached at anapoliello@njadvancemedia.com. Follow him on Twitter @alexnapoNJ. Find NJ.com on Facebook.