The bell chimed and after a little while a voice croaked through one of those electrical contraptions that let you talk with your front door locked.

铃声响起，过了一会儿，一个声音从那些电子装置中传来，这些电子装置可以让你在前门锁着的情况下说话。

The inspector began to look for fingerprints, while the constable checked that the front door locks had not been forced, thereby proving that the burglars had either used skeleton keys or entered over the balcony.

检查员开始寻找指纹，而警员检查前门锁没有被强行锁上，从而证明窃贼使用万能钥匙或从阳台进入。