HINT 01
Compare this text chain with another text chain.
HINT 02
The person texting is someone that Chloe hates, and the person who owns the phone knows this.
HINT 03
Another piece of evidence will help to make the correct connections.
HINT 04
Perhaps the device description will come in handy. Where else have you seen a phone case in that colour?
ANSWER
It’s clear from reading the text chain that Jack is on bad terms with Chloe. This is also evident from the fact she’s scrubbed his face out of her New Year’s Eve photo. The same photo shows that Jack and Jade know each other, and it shows that Jade has a mobile phone with a pale pink flip cover (as described in the record of communications).
As this number was also the one texting Chloe’s phone, it must be a good friend of hers. Hence, these texts come from Jade’s phone, and the person texting Jade is Jack.