The handwritten letter was picked by a man who informed the temple authorities and the police about it.
"There is no mention of any specific target in the handwritten letter which is a photocopy and not the original. Prima facie, it appears a prank but security arrangements have been strengthen and CCTV footage is being examined to identified the person who dropped the letter there," SP Sikar Dr Ravi said.
A student preparing for medical entrance examination was also held yesterday for allegedly posting threatening messages on a social media (WhatsApp) site.