Swinson has toughened her party's anti-Brexit stance since taking over as leader in July, promising to cancel Brexit if the Liberal Democrats score an unlikely victory in a widely expected early election.
During the launch of her party's general election campaign, Swinson said that there was no difference between Labour and Conservatives and both parties want Brexit.
On Monday (November 4) ITV reported that Swinson was the recipient of suspicious package delivered to her office in parliament.
London's police said they were alerted to the package just before 1000 GMT on Monday in Portcullis House, where many lawmakers have their offices.
The police later ruled it was non-hazardous.