Grandmother foiled possible school attack day before Florida massacre

"That would have probably been one of the hardest calls she has probably ever made, but I think that the content of the journal and some of the other evidence in the house was enough that she was alarmed enough", Everett Police Officer Aaron Snell said. According to the Seattle Times, the grandmother called 911 and relayed what authorities later described as "upcoming and credible threats" to ACES High School.

Police contacted school officials about the alleged threat, and then arrested the student at ACES High School.

"I'm preparing myself for the school shooting", he wrote, according to the newspaper.

Detectives, serving a search warrant on February 13, reportedly found an AK-47 and inert grenades in the 18-year-old's bedroom.

Joshua Alexander O'Connor was charged with attempted murder.

. The entries also included details about making pressure-cooker bombs, activating inert grenades and deploying explosives for maximum casualties.

Following the news of a thwarted attack, Muntz, the spokesman for the Mukilteo School District, praised O'Connor's grandmother for calling the police and turning in her grandson. "My aim has gotten much more accurate.I can't wait to walk into that class and blow all those [expletive] s away".

"I need to make this count", O'Connor wrote, according to the paper. "I've been reviewing many mass shootings/bombings (and attempted bombings) I'm learning from past shooters/bombers mistakes".

He also reportedly wrote that he wanted to get "the biggest fatality number I possibly can", CBS reported.

Authorities say the teen detailed how he planned to shoot students and detonate homemade explosives. The records state that officers found marijuana and a knife in his possession and took him into custody.

The arrest came just 24 hours before the killing of 17 people at the Marjory Stoneman Douglas High School in Parkland, Florida. A search of O'Connor's room also revealed that he was involved in the two-person armed robbery of a nearby convenience store Monday, prosecutors allege.

Public defender Rachel Forde said the weapon and the grenade shells were legally owned, according to the Daily Herald.

The judge found probable cause to keep the case moving, setting a high bail of $5 million. He was booked into the Snohomish County Jail on probable cause for attempted murder due to planning and taking substantial steps toward executing a school shooting. "That couldn't have been easy for her to do".

"Her actions may have saved many lives and underscores the importance that if you see or hear of something suspicious, you need to notify authorities", he said in a statement to The Washington Post.

Police said once the suspect was at the Everett Police Department South Precinct, he managed to get one of his hands out of the handcuffs and then ran across the parking lot.