The emails, copies of both of which were obtained by ABC News, each begin by addressing "To Whom It May Concern" and say, "I am emailing you to inform you of the happenings on Tuesday, 12/15/15. Something big is going down. Something very big."
In both emails, the sender says he or she has suffered bullying at "one of the district high schools" and says he or she is a "devout Muslim" that has joined up with a "local jihadist cell" to perpetrate an attack.
Each email claims bombs have been hidden in lockers at several schools and that the supposed attack would also involve "nerve gas agents" and a follow-on armed attack with specific weapons.
Beyond targeting different school districts, the emails do show some small differences, however. In the Los Angeles email, the sender claims to have "32 comrades," whereas in the New York email, the number grew to 138.
Speaking to reporters Tuesday, Bratton seized on the New York City email's apparent error in its failure to capitalize Allah. "That would be incredible to think that any jihadist would not spell Allah with a capital 'A,'" he said. But the Los Angeles email manages to capitalize the word.
At the end of the New York email, the sender also threatens nearby cities by name, exactly the way the sender threatens other nearby cities in the Los Angeles email.
In both cases officials said the emails appeared connected to a server abroad and the copy of the Los Angeles email identified the email hosting service. The owner of the service, identified Tuesday by The Verge, is cooperating with authorities, according to his attorney.
Los Angeles canceled school Tuesday in light of the threat Tuesday, prompting some criticism in New York, from Bratton in particular, for "overreacting." Los Angeles school officials said they closed the schools out of an abundance of caution in the wake of the San Bernardino shootings earlier this month that claimed 14 lives.
ABC News' Rhonda Schwartz contributed to this report.