How to build an investigation timeline

The desk asks you to say how you know a time. There are four answers:

• Recorded. A clock, camera or log captured it.
• Remembered. Somebody remembers it or estimates it.
• Worked out. You calculated it from other evidence.
• No source given. You have not said. Try not to leave it that way.

A witness’s “around half eight” and a camera’s 08:17:42 are not the same kind of fact, and a good timeline never pretends they are.

• Recorded: 08:17:42, from the camera.
• Remembered: about 08:15, from the neighbour. Write it as 08:15, and say it is remembered.
• Worked out: about 08:21, from the receipt minus ten minutes. It is only as good as the shopkeeper’s ten minutes.

Three times, all within six minutes. Do not average them. Keep each with its source. The desk will ask whether times within 15 minutes of each other are the same moment, and joins them as two sources of one moment if you say yes.

A report often carries several times, and they are not the same. One is when something happened, another is when it was reported, and a third is when the report was written. Put each on your timeline for what it is. “Reported at 09:05” is a recorded time, but it tells you about the call, not about the event.

Once a few times are in, look for the quiet stretches. On the desk, two hours or more with nothing on your timeline shows as a band, such as “2 h 34 min with nothing on your timeline”.

For each gap, ask:

• Who was where? Does anybody have only their own word for it?
• Did a camera or log cover this stretch? If not, why not?
• Does a time on either side look too tidy?

You can add a gap straight to your questions, using your own two times.

Label each time as recorded, remembered or worked out. These are invented too.

1. “The depot log shows the bin lorry leaving the yard at 06:52.”
2. “Mrs Ames says the lorry woke her up, just after seven.”
3. “The lorry takes 25 minutes from the yard to the lane, so it arrived about 07:17.”