The CDs of the speeches will undergo forensic scrutiny, Inspector General of the Special Task Force Ashish Gupta said.
"The CDs have been sent by observers of the poll panel and are now being checked, among other things, for authenticity," an official told IANS.
Chief Electoral Officer Umesh Sinha also said the poll panel was monitoring the developments on a day-to-day basis. "Anything and everything to ensure free, fair and peaceful elections in the state is being done," he added.
The step came after first information reports (FIRs) were registered with police on the instructions of the Election Commission last week.
Questions are being asked on the delay in arresting the two leaders, given that Congress candidate from Saharanpur, Imran Masood, was promptly arrested for his hate speech against BJP's prime ministerial candidate Narendra Modi.
Masood, in a speech taped on a cell phone, was shown threatening to cut Modi into pieces if he (Modi) set his foot in western Uttar Pradesh.