OK then, I'll ask you some questions:
Why was the puppy outdoors at night, in the first place?
If you knew your other dog was prone to digging a hole in a particular spot,why didn't you reinforce the area?
Why have you left a puppy in an unsecured garden?
I, too, have kept dogs all my life. At the front of my house is an extremely busy main road, half a block away is another busy road which leads on to the main one.
I have a 90ft garden, overlooking farmland at the back, where the farmer drives his 4 X 4, his tractors and this week, a combine harvester - so you can imagine that keeping my young dog secure in my garden is pretty high on my list of priorities.
I got Sam Pup when he was 12 weeks old, after he was found lost or just abandoned, wandering around busy streets on his own.
I can just imagine the reaction of the Labrador Rescue inspector, when she asked me if the garden was secure, if I'd said: 'Yes, but if he does start digging and can get out, I'll buy a shock collar. He'll soon learn ...'
Somehow, I don't think I'd have been allowed to adopt Sam.
The only safe way to keep a puppy in a garden is to supervise it and never leave it alone, especially when you think it might try to get out.