This is a sample of the definition for Murder in the Second Degree in Dean's Law Dictionary.
A killing of a person without premeditation or deliberation but with malice aforethought.Murder in the second degree, occurs when a killing is done, without premeditation or deliberate mind required to make the act murder in the first degree, but where it is done without justification or excuse, and without adequate provocation, and when it was done with a wicked and depraved heart, or with a cruel and wicked indifference to human life. In a case of that kind, the law implies malice and renders it incumbent upon the accused to show by evidence that the killing was not in fact malicious, or that there were circumstances of mitigation, extenuation, justification or excuse. Ruffin v. State, 11 Terry 83, 123 A.2d 461 .
A specific intent to take life is an essential ingredient of murder in the first degree. At common law, the 'grand criterion' which 'distinguished murder from other killing' was malice on the part of the killer and this malice was not necessarily 'malevolent to the deceased particularly' but 'any evil design in general; the dictate of a wicked, depraved and malignant heart.' Coolly discharging a gun among a multitude of people', causing the death of someone of the multitude is malice for murder. Murder of the second degree includes every element which enters into first degree murder except the intention to kill. Commonwealth v. Divomte, 262 Pa. 504, 507; 105 A. 821.
When an individual commits an act of gross recklessness for which he must reasonably anticipate that death to another is likely to result, he exhibits that 'wickedness of disposition; hardness of heart; cruelty; recklessness of consequences and a mind regardless of social duty' which proved that there was at that time in him 'that state or frame of mind termed malice'. These quoted phrases are from the opinion of Chief Justice AGNEW in Com. v. Drum, 58 Pa. 9. If a driver 'wantonly, recklessly and in disregard of consequences' hurls 'his car against another or into a crowd' and death results from that act 'he ought to face the same consequences that would be meted out to him if he had accomplished death by wantonly and wickedly firing a gun': Com. v. Mayberry. 290 Pa. 195, 199; 138 A. 686, citing cases from four jurisdictions. .....