I'm new to both querying and to this board, so I hope that I'm doing this right and that I'm not providing you useless feedback. First of all, I think that this query is very intriguing, and I would certainly buy your book based on it! I will note that I read your comment at the beginning that you'd posted a revised version here, so I didn't read the prior comments because I didn't want to be biased/have extrinsic information when I read this so I could give you feedback based on the information in the latest version alone. My comments are in red below.
For sixteen-year old Tanvi, her cousin Mimi’s death is just a painful memory. But that changes the day she comes home from school to find Mimi’s name scrawled across her bedroom wall and her aunt searching for her deceased daughter. [These two sentences make me wonder how much time has passed between her cousin's death and "the day she comes home from school." Not sure if you could sneak in some context in this opening paragraph without making it too dense.]
When Tanvi spots a girl who’s the spitting image of Mimi, she understands what triggered her aunt’s delusions. [I agree with the poster above that I'm not clear what "seeing" the girl means in this context. Could you add a little something above that explains what her aunt saw/what triggered her search or add a little information here that could provide some context...eg. "when she spotted her at Starbuck's, grabbing her mocha latte from the barista" has a different connotation than "when she spots the girl for a moment in a crowd"? Part of this might be that it's not clear to me from the above whether the implication is that Mimi/the double scrawled the name or the aunt did. Did the aunt see her and go a little off the edge, or did the name on the wall trigger the delusions? I think that you're doing a great job of balancing providing enough details to intrigue the reader without giving too much away, but I was a little bit confused by this.] Then the girl starts stalking Tanvi, running her off the road, and even implicating her in a local bully’s death [this is great, because it suggests that other people see the double besides Tanvi and possibly her aunt]. Tanvi soon finds out that the lookalike also knows about her past, especially her mom’s involvement with dark magic from India.
To unmask the lookalike [I agree with the poster above that "unmask" in this context is not clear--does she need to prove to others that the double is not her cousin, or is this an evil creature that can assume her cousin's form and she needs to figure out what the creature is so that she can stop it]?, Tanvi must find the truth behind her cousin’s death. But her search is complicated by flashbacks into her [Tanvi's or her cousin's?] past and visions of dark magic rituals. The closer she gets to the truth, the more she spirals into these hallucinations [But are they potential hallucinations or are they definitively in her head? By referring to them as hallucinations, it feels less ambiguous to me.].
Defeating Mimi’s homicidal double at her own game could cost Tanvi her sanity, if not her life. [great establishing the stakes! and great way to end!]
MAKING AMENDS, a YA psychological thriller, is complete at 72,000 words.
Thank you for your time and consideration. I look forward to hearing from you.
In my 100% non-expert opinion, I really like your story/concept and think that your query letter is very strong. In fact, I am jealous because it seems to pack so much in without being wordy, which is the problem I'm running into! Good luck with querying!