Bloody Valentine by K. A. John (with maybe a line or two by James Patterson so his name can be on the cover) is an all right read to pass the time, however as far as the Quick Reads short story series go, most of the other books in the series are a lot higher quality than this one. Bloody Valentine is just another entry into the already saturated through the eyes of a homicide detective fiction genre.
Bloody valentine's plot follows Inspector Amy Stuart, who has been assigned a particularly gruesome case, where the heart supposedly (we know it is as we read her murder at the start, which is the only slightly entertaining part of the book) belonging to Zee Barnes, the young pregnant wife of high profile and extremely wealthy restaurant owner Jack Barnes. It has been express delivered to his office. They know the victim has been recently murdered and on the assumption it belongs to Zee, track her movements for that morning before she disappeared. It becomes apparent (for the story to work not realistically so) that the murderer had to have been in the Barnes luxury block of flats that morning. Each of the apartments is inhabited by a relative of Jack Barnes. All people coming and going are recorded on security cameras and need codes to get around the building. Inspector Stuart and the police officers assigned to the case have gathered all the relatives in the buildings common room. Problem is all of the occupants are snobby stuck up self centred people who think they are above being bothered by such things as a homicide investigation. Plus none of them liked the fact Zee a young waitress married into their family. Which one of them murdered Zee?
Bloody Valentine is part of the Quick Reads series. If you're unfamiliar with the Quick Reads initiative, they are books published to increase literacy levels by encouraging those who don't like to read beyond magazines and comic books, to try fiction through cheap priced (current Quick Reads all sell of the rack for under two pounds in the UK) short story length fiction and non fiction. I don't think Bloody Valentine is good enough to encourage those who are trying fiction for the first time or retrying fiction for a while to want to keep reading other short stories or full length novels. It also suffers from the lazy divulging who did it ending, of the supposedly intelligent enough to do everything to avoid forensic evidence killer, just confessing everything and their motives.
The other problem you've got is an ethical one, with no mention of co-author K.A John on the cover, unless you pick this up and flick through it to the copyright cover page readers will buy this expecting it to be all James Patterson. Which is a reasonable assumption to make when you also consider it's a short story (122 pages).