By Daniel Kelley

PHILADELPHIA (Reuters) - A suburban Philadelphia teen charged with attempted murder in connection with a ricin-laced birthday card sent to try to scare off a romantic rival is headed to trial.

Nicholas Helman, 19, appeared in court on Thursday to face a charge that he placed the envelope containing traces of the deadly poison, which is made from castor beans, in the mailbox of his ex-girlfriend's new boyfriend in March.

Acting on a tip from one of Helman's co-workers, police intercepted the letter before it was opened. In a later raid of the suspect's home, investigators found a backpack containing castor beans and other materials that can be used to make the poison, according to prosecutors.

The former Eagle Scout was caught, according to court documents, after he bragged to a co-worker at a local retail store about rubbing ground castor beans onto a scratch-and-sniff birthday card.

He told police he was only trying to frighten his ex's new beau as part of a scheme to win her back, according to a police affidavit.

In an online profile created while he was a high school junior, Helman described himself as extremely interested in science and math.

Antonetta Stancu, an assistant district attorney prosecuting the case, said the ricin in this case had the markings of being made by an amateur but that it was still dangerous.

"If you inhale this, it's deadly," Stancu said.

Prosecutors charged Helman, who is being held without bail, with attempted murder and risking a catastrophe. His trial is scheduled to begin in June.

(Editing by Scott Malone and Gunna Dickson)