Delay in deduction of tds

dear sir

one of my friend had not deduct T.D.S. on rent receipt on behalf on trust, since the tenant shown a letter copy which was written to I.T.Dept., seeking exemption during last feb.,2014.

Hence TDS was not deducted from April to June. But the tenant get exemption from July 2014 onwards.

Now my friend has to deduct TDS for 3 months ie., April to June and has to pay with interest.

Is it correct? and whether late deduction and payment of TDS attract penalty also.

please clarify.

thanks