知らせてきた

let me know

→ 知らせる
phrase Rare #42,260
let me know Past form of 知らせてくる, meaning that someone informed the speaker or came to report something to them. The subject is usually someone other than the speaker.
JA: 母から、無事に着いたと知らせてきた。
EN: My mother let me know that she arrived safely.

彼は私に到着したことを知らせてきた

He let me know that he had arrived.

彼は盗難車を見た知らせてきた

He reported that he had seen the stolen car.

彼女が新しい金持ちの彼氏が出来た知らせてきた時、彼はほっとしました

He felt relieved when she told him she had a new rich boyfriend.