HATBORO, Pa. -

A Montgomery County teenager sent a romantic rival a birthday card laced with the deadly poison ricin, authorities said.

Police arrested Nicholas Helman on Wednesday at his home in Hatboro. He was initially charged on March 7 with harassment, but that count was withdrawn and he was arrested Wednesday evening on a charge of attempted murder.

Investigators alleged Helman told a co-worker that he had sent a poisonous birthday card to his ex-girlfriend's current boyfriend. The co-worker called police.

Authorities said ingredients for making ricin were recovered from Helman last week, and preliminary testing on the birthday card tested positive for ricin.

In addition to attempted murder, Helman is also facing charges of aggravated assault, risking catastrophe, talking, terroristic threats, simple assault, possessing an instrument of crime, harassment and recklessly endangering another person.