Not bad. Succinct and intriguing.
Dear Agent,
When sixteen-year-old Bridget Ferns finds a dead cheerleader in the janitor’s closet, she fears that she might be the killer’s next target.
She is.
I like the janitor's closet detail.
Being a teenage telepath, Bridget’s mind possesses the only clues leading to the killer’s identity
Subject agreement: "Bridget's mind, being a teen telepath." Isn't it Bridget who is the teen?
As someone who knows the shocking truths that pass through her classmate’s heads, Bridget’s investigation leads her to
Subject agreement: "Bridget's investigation, as someone who knows the truths." The investigation isn't a someone who knows.
suspect the one person she trusts most – her boyfriend Terrence, the only person whose thoughts she can’t read.
Awkward sentence: How about simply "leads her to the person she trusts the most..." Dropping the "suspect the one" is more direct and loses the redundant one/only. It still leaves a double "person".
Now someone is taunting her, calling her name when the halls are empty. But when Bridget tries to expose her tormentor, she’s nearly beaten to death by a mind controlled minion with fiery eyes.
Good.
When Bridget finds the killer’s hideout she stumbles upon a horde of brainwashed classmates all programmed to destroy her life.
Good, but repeats the "When" to start the sentence, of the previous sentence.
The killer wants more than Bridget’s blood, the killer wants her soul and the mind reading abilities that come with possessing it.
How can he want her blood (to kill her?) and be able to make use of her abilities? Wouldn't he want her alive, or is this an ability that can be transferred to him?
Also, a bit awkward, sounding like a run-on sentence, "the killer, the killer" and I'm not quite on board with the double "the killer."
Bridget must discover the killer’s true identity while keeping her abilities a secret. If she’s forced to take part in this soul-sucking ritual, Bridget risks watching her loved ones die before it’s her turn. But if she survives her Junior year, the entire school will have learned her secret.
Okay, but not entirely clear what is at stake for her. Sounds like it's only her secret. What are the consequences of others knowing her secret?
Also, there's a disconnect between "forced" and "risk". Risk usually (or at least more dramatically) implies a voluntary choice or step. You've undercut the weight of this by having her potentially forced, having no choice in the matter.
[Bio info]
Be nice to know your genre and word count.
Good, generally. I'd say fix the grammar and ratchet up the tension at the end. The crux must be clear and mean something to (emotionally grip) the reader.
