Mrs Bortz
The Mystery of The Invisible DogMrs Bortz is the red-haired, bespectacled manager of the apartment building where Fenton Prentice lives, and an apparent guardian of its tenants’ privacy who has secretly violated one tenant’s. Her unauthorized access to Prentice’s apartment supplies a concrete answer to the mystery of how someone could inspect his private papers and belongings: she arranged to have a second key made while he was away in Europe.
Identity and First Appearance
Mrs Bortz first confronts the boys at the gate to the Paseo Place apartment courtyard pool. Thick-bodied and red-haired, she peers at them through rimless glasses and sharply rejects the possibility that they are solicitors or collectors. She says she does not want her tenants disturbed, establishing her as someone who polices access to the building and speaks with the authority of its manager.
The abruptness of that greeting sets up a contrast central to her role. Mrs Bortz presents herself as a defender of tenants against unwanted intrusion, yet her own conduct toward Prentice crosses the boundary she claims to protect. The contrast is not merely between her public manner and private behavior: it links her management of the building to the investigation’s question of who has been watching Prentice.
The Second Key and the Apartment Search
Prentice confirms that Mrs Bortz had a key to his apartment. His lease contained a special clause stipulating that the manager was never to enter, making her access especially significant. The key also explains how the investigators’ suspicion of a second means of entry could be resolved without requiring an unknown intruder to have picked the lock.
Mrs Bortz had the key made while Prentice was in Europe two months earlier. She called a locksmith who often worked for her and told him she had lost the key and needed to enter the apartment to check for a leaking pipe. He removed the lock, made her a key, and replaced the lock. The account describes a specific, indirect way of obtaining access: she relied on her established dealings with the locksmith and gave him a practical reason to replace the lock, without telling him that Prentice’s lease barred the manager from entering.
Exposure as the Spy
Jupiter Jones confronts Mrs Bortz with the substance of the intrusion: she had been inside Prentice’s apartment, opened his desk, looked through his mail, and opened his medicine cabinet. He calls her the spy. The accusation identifies not simply an unauthorized entry but a search reaching across several kinds of private material, from correspondence to personal storage.
Prentice’s confirmation of the duplicate key reinforces the accusation with a chain of concrete circumstances: his absence, Mrs Bortz’s request to the locksmith, her explanation about a lost key and possible leak, and the replacement of the lock. The evidence establishes her access and snooping, but does not specify what she hoped to discover or whether she acted for any further purpose. Her significance in the mystery lies in the revealed breach itself: the building manager who had rebuked visitors for disturbing tenants had secretly entered a tenant’s home and examined his possessions.


