Yes.  In order to try, I installed telnetd in a sandbox, and it seems to work fine (i.e. ->cmd("\cC") actually does get a SIGINT being delivered to the tail -f).

...
$telnet->print("/path/to/script") or die $telnet->errmsg;
$telnet->print("tail -f /tmp/testxxx") or die $telnet->errmsg;
$telnet->waitfor('/FINISHED/');

$telnet->cmd("\cC") or die $telnet->errmsg;

... (run next script)
[download]

where script goes in the background and writes a few lines to /tmp/testxxx, with the last line being "FINISHED".