Andre,
It appears that Büchen and area fell under the responsibility of the British. Judging by this link
http://rzkultur.de/index.php?kat=31&cont=8492 a British armoured brigade passed in the vicinity just four days later.
I'm sure you're familiar with this one:
http://www.ln-online.de/magazin/ratg...brissbirne.htm
An RAF raid comes to mind, as proposed by other forum readers.
I understand some 200 people were killed in Büchen in the air raid?
Regards,
Leendert