A detective agency with 事務所
Kanji Explanation: Matters and events with 事

After returning home from a case, Kogoro celebrates by drinking himself to sleep. Ran sits alone, pondering Shin’ichi’s whereabouts, as she hasn’t heard from him since the day he mysteriously vanished. The phone rings. With her father asleep, Ran answers it.
- 蘭:
- 「ハイ… 毛利
( 探偵( 事務( …」- “Hello... Mouri Detective Agenc--”
Key Points
Set phrase on the phone: 毛利
( 探偵( 事務所( Ran is answering with the name of the office, like saying “Mouri Detective Agency” when picking up.
The line in-panel cuts off after 事務
( …, but the intended phrase is 事務所( .
Why only 事務
( appears事務
( means office work or administrative work by itself, but here it is the beginning of 事務所( .The interruption in the next panel explains why she does not finish the full word.
Polite opening
ハイ… is a natural phone-answer opening (similar to “Hello?”), followed by the office name.