but its not just opening them its closing them and locking them behind you.
"Later the appellant said he had decided to shoot his family and he told her that he had discovered that the catch on the kitchen window did not work and he could gain access to the house in that way. The appellant said he planned to leave the address by a different window, which latched when it was shut from the outside. He spoke of Sheila Caffell being a good scapegoat because of her admission to hospital during Easter 1985 and said that afterwards he would make it seem as if Sheila had done it and then killed herself."
"The appellant returned the moderator to the gun cupboard and before leaving the address called his home at Goldhanger, leaving the receiver off the hook, thus lending support to the alibi he would later rely upon. He then left the premises, one available route being to climb out of the kitchen window, banging it from the outside to drop the catch back into position and then cycled home."
These quotes are from the 2002 appellate decision. The police investigated the kitchen window in response to the following claim which also is quoted in said appeal decision:
"It is also of significance that he recorded on 20 August 1985:
"They (Robert Boulflour and Ann Eaton) thought the windows could be locked from outside the premises making particular reference to the window behind the bushes by the Geese pond facing towards the tennis court".
This would appear to be the kitchen window and provides the explanation for DC Barlow's examination of the kitchen window."
Barlow went and examined the Kitchen weindow in response to their claim and it was determined the catch could be closed from the outside. Hence the prosecution argued at trial that is how Jeremy left the house.