CHESTER, Pa. (WPVI) --The 23-year-old suspect allegedly made the threats to police in response to a teenager's social media post threatening an attack on her school.
He was arraigned and faces serious charges.
According to authorities, Milbourne's actions were in response to a Chester High School student's Tuesday night social media post threatening to "shoot up" several Chester area schools.
In that case the 17-year-old African American female included emojis of guns and knives and wrote all blacks must die. Police say the fake account she created included an Aryan nation symbol.
She was arrested hours later by the FBI and local authorities at her aunt's house in the 1300 block of Harshaw where she was sleeping over.
Law enforcement acted quickly and were able to arrest both Milbourne and the 17-year-old Chester High School student.
Delaware County District Attorney Jack Whelan says, "We didn't know what we were going to find. We didn't know if we were going to find an individual with numerous weapons."
Police say Milbourne and the 17-year-old student confessed to the threats and officers say both also wrote about it on Facebook.
In one online rant, Milbourne allegedly wrote: "Tell them stupid Chester cops...they better worry about their family getting murdered."
Whelan says Milbourne may have some mental health issues.
"He said irrational and illogical statements and I wouldn't be surprised but we haven't documented a mental condition at this point," Whelan explained.
Police don't believe the two knew each other, but say they may have been in contact via social media.
Officers don't believe either threat was credible but say they have to take any potential attack against schools or law enforcement seriously. They warn -- if you think you can hide behind a keyboard - think again.
Whelan says, "You post a threatening message, you post something against law enforcement and their families, you post something against students in an educational facility, we are coming with our team of investigators."
Police also said they would like to thank the community for their tips in reporting these cases.
As for the 17-year-old suspect, her name is not being released because of her age.
It's also important to mention, that police say they don't believe either suspect had the ability to act out on the threats.