MacOS – El Capitan froze and rebooted (Macbook Pro Retina Mid 2012)

• 2.3 Ghz Intel Core i7 8GB DDR3:
  Was running NetAdmin Pro which is monitoring
  my office LAN, processors consumption was at
  ~15 – 20%. Simultaneously I ran WiFI Explorer,
  3.7% no more than 5% CPU usage. And I was
  updating Xcode to v 7.3.1 and was browsing and
  watching video from playground.ru

• Watch the videos until half of it (20mins) the
  Video froze I moved the mouse and turned out
  the whole OSX is frozen.

• littleSnitch v 3.7 has no reaction

• I immediately pull the Ethernet adaptor and
  MacBook just went to black screen. I then
  switch off the wireless router. (My MacBook Pro
  is connected to the network via Ethernet
  adaptor and via WiFi router bearing different IP,
  I was thinking of cutting both network
  communication, in case it was an intrusion)

• MacBook just restarted itself to login screen,
  after 15-20 sec of black screen and total
  silence)

• I again restarted and booted into Recovery
  mode use disk utility. After completing disk
  check.

• Login and previously opened programs resume
  back (NetAdmin Pro, WiFi Explorer, Yandex
  browser, Activity Monitor and AppStore)

• AppStore doesn't resume the download
  everything else is functioning normally and in
  Addition I have got my calendar open after login
  (I did not launch accidental nor was it set to
  start with system login)

Question 1: Are there any way to know what was happening and what was OS El Capitan last reaction before it froze and rebooted?

Question 2: Are there any software better than "Console" v10.11 to interpret what was going on before it crashes?

P.S. Thank you in advance, I will try to upload the Console messages later from the MacBook Pro

DDT-2:~ Chaleune$ syslog | grep -i "shutdown cause"

Jun 22 14:15:37 DDT-2 kernel[0] <Notice>: Previous shutdown cause: 5

Jun 22 20:34:46 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 23 15:18:23 DDT-2 kernel[0] <Notice>: Previous shutdown cause: 5

Jun 24 17:58:32 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 24 20:09:52 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 24 22:58:15 localhost kernel[0] <Notice>: Previous shutdown cause: 5Jun 25 14:43:36 DDT-2 kernel[0] <Notice>: Previous shutdown cause: 5

Jun 25 21:55:31 localhost kernel[0] <Notice>: Previous shutdown cause: 3

Jun 25 22:20:57 localhost kernel[0] <Notice>: Kext com.apple.driver.AppleOSXWatchdog failed to load (0xdc008012).Previous shutdown cause: 5

Jun 26 10:18:44 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 26 12:09:45 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 26 18:00:31 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 27 13:05:58 DDT-2 kernel[0] <Notice>: Previous shutdown cause: 5

Jun 27 22:56:11 localhost kernel[0] <Notice>: Previous shutdown cause: 5

Jun 28 14:18:27 DDT-2 kernel[0] <Notice>: Previous shutdown cause: 5

*Jun 29 18:56:21 localhost kernel[0] <Notice>: Previous shutdown cause: -128*

Jun 29 23:31:22 DDT-2 kernel[0] <Notice>: Previous shutdown cause: -128

Opensource.apple shows the following

• dsIllInstErr = 3, /illegal instruction error/
• dsChkErr = 5, /check trap error/
• userCanceledErr = -128

macwizard gave the following interpretation:

• 03 Illegal Instruction
  The computer has a specific vocabulary of machine language instructions it can understand. If a computer tries to execute an instruction that isn't in its vocabulary, you see this error code. It's less likely than error 02, but still very common.
• 05 Range Check Error
  Programmers can use an instruction in the Motorola 68000 to check if a number is within a certain range. This error indicates that the number tested isn't in the specified range.
• -128 userCanceledErr User canceled an operation