The Horagolla Walawwa is the ancestral home of the Bandaranaikes, including former president Chandrika Bandaranaike Kumaratunga.
The intruder had entered despite the presence of the Presidential Security Division and a police post in front of the Bandaranaike memorial.
Investigations have revealed that the intruder had broken the lock of the back door before entering the property.
However, the former president had not been at the premises when the incident had taken place.
It is said that 3 PSD officers have been on duty.
The Nittambuwa police and Colombo Crime Division are holding further investigations.